You can't reference the type in your view because it is an anonymous type. Instead, define a type to store the results of your query:
public class Result
{
public string Name { get; set; }
public int Count { get; set; }
}
Then change your query to project into that type:
var allU = (from m in comList
join c in users on m.user equals c.user into cm1
from cm2 in cm1.DefaultIfEmpty()
group cm2 by m.user into grouped
select new Result { Name = grouped.Key, Count = grouped.Count() }).AsEnumerable();
Then you'll be able to bind to the type IEnumerable<Result>
in your view.