Problem with validating blocked users Laravel

I have a site which I have a function to validate if the email entered belongs or not to a user in blacklist (Blocked User). Which for the case that is fulfilled should not allow sending the form.

What validation should do is, validate if the email entered is the same as an email from a user that is on the blacklist. To get that email the validation will ask first if the user id of my TABLE Blacklist , is equal to id of my user table and finally ask if that user's email is the same as the email received from the form.

As for example, the following query shows me the users that I have in the blacklist, that is, blocked.

In other words, the validation must follow the same order of the query in a similar way, plus the email received from the form.

This is the form.

<form name="form" action="{{route('miruta')}} method="POST">

  @foreach($user as $user)
    @foreach($lista_negra as $lista)
      @if($lista->user_id == $user->id)
         <input type="hidden" id="user_email" value="{{$user->email}}">
         <input type="hidden" id="user_name" value="{{$user->name}}">
      @endif
    @endforeach
  @endforeach

  <table>
    <tr>
      <td>Responsable</td>
      <td>
        <input type="email" name="responsable" id="responsable" required="required">

        <br><br>
        <textarea maxlength="500" id="comentario" name="comentario"></textarea>
      </td>
    </tr>

    <tr>
      <td>
       <!--CONTENIDO-->
      </td>
    </tr>
  </table>

  <input type="submit" name="guardar" id="btn-guardar" value="CONFIRMAR"/>
</form>

I have been testing to perform the validation on my controller, as follows:

public function guardarReserva(Request $request){

  $monto = $request->codigo;

  if($request->isMethod('POST')){

    $id_complejo=$request->input('complejo');
    $horario=$request->input('horario');
    $indumentarias=$request->input('indumentaria');
    $responsable=$request->input('responsable');
    $fono_responsable=$request->input('fono_responsable');
    $comentario = $request->input('comentario');

    $id_descuento=0;
    $fecha_reserva=date('Y-m-d H:i:s');


    $listaNegra = DB::select('select users.email from lista_negra join users where lista_negra.user_id like users.id');


    //CONDICION - ¿COMO PODRIA COMPARAR EL ARRAY $listaNegra?
    if ($listaNegra == $responsable) {

        Session::flash('error', 'El usuario'.' '.$user_name.' '.'no se puede utilizar como responsable debido a que se encuentra en Lista Negra');
        return Redirect()->back();
    } 

    //SEGUNDA FORMA
    $user_blocked = $request->user_email;

    if($user_blocked == $responsable){
      Session::flash('error', 'Este usuario no se puede utilizar porque se encuentra bloqueado');
    return redirect()->back();
    }

    //AL HACER UN dd($user_blocked == $responsable) OBTENGO true COMO RESULTADO


    //VISTA FINAL QUE ES RETORNADA
    return view('reservar-cancha-exito',['id'=>$rid,'hora_inicio'=>$hora_inicio,'complejo'=>$complejo,'hora_fin'=>$hora_fin,'monto'=>$monto,'cancha'=>$cancha,'descuento'=>$monto_descuento,'fecha_reserva' => $fecha_reserva,'indumentarias' => $indumentariasArr]);
  }

}

Which when doing a dd($listaNegra, $responsable) I get the following:

  

IMPORTANT: The photo is edited to explain which email is received by the variable $request

Finally the validation does not work in any of the 2 ways. And I do not receive any error, for the first case in exchange for the second I receive an error that says NO MESSAGE .

What could I have done wrong? As extra information I leave the main models that I occupy.

The model for the blacklist.

<?php

namespace App;

use Illuminate\Database\Eloquent\Model;

class ListaNegra extends Model{

  protected $table = "lista_negra";
  protected $fillable = ['name'];
}
?>

And the model of the user.

<?php

  namespace App;

  use Illuminate\Auth\Authenticatable;
  use Illuminate\Database\Eloquent\Model;
  use Illuminate\Auth\Passwords\CanResetPassword;
  use Illuminate\Foundation\Auth\Access\Authorizable;
  use Illuminate\Contracts\Auth\Authenticatable as AuthenticatableContract;
  use Illuminate\Contracts\Auth\Access\Authorizable as AuthorizableContract;
  use Illuminate\Contracts\Auth\CanResetPassword as CanResetPasswordContract;

  class User extends Model implements AuthenticatableContract, AuthorizableContract,CanResetPasswordContract{

    use Authenticatable, Authorizable, CanResetPassword;

    protected $table = 'users';

    protected $fillable = ['id','name', 'email', 'password','LastName','sLastName','telephone','role_id', 'complejo_id'];

    protected $hidden = ['password', 'remember_token'];

    public function setPasswordAttribute($valor){
        if (!empty($valor)){
            $this->attributes['password'] = \Hash::make($valor);
        }
    }
  }
?>

I have also tried the view in the following way, without getting the expected result, which is to show an alert to the user preventing the form from being sent.

<script type="text/javascript">

  var name_user = document.getElementById('user_name').val();

  $(document).ready(function(){
    $('#btn-guardar').click(function(){
      $("#user_email").each(function(e){

        var user_mail = $('#user_email').val();
        var email_usuario= document.getElementById('responsable').value;

        if(email_usuario == user_mail){
           e.prevenDefault();
           $('#responsable').focus();

           $.alert({
            title: ''+'<nav style="background: #478573; color: white; width: 20cm;height: 10mm; margin-top: -5mm; margin-left: -5mm; padding-top:2.5mm; padding-bottom: 6mm;">&nbsp;&nbsp;<i class="fa fa-times"></i>&nbsp;&nbsp;¡Error!</nav> ',
            content: ''+'<label style="color: black; font-weight: 500;">El usuario (@'+name_user+') no se puede utilizar ya que se encuentra bloqueado.</label>',
          });
          return false;
        }
      });
    });
  });
</script>