People are afraid to say even innocent or true things because those will result them being branded as "racist". For example even good liberals who believe that black communities are caught in a cycle of crime, have to self-censor because the only acceptable position is that black crime is entirely caused by a biased criminal justice system.
I don't think Trump phased it very well but I do think that illegal immigration is a net negative for the US, and it wouldn't' surprise me if illegal immigrants were disproportionately criminal. What's undeniable is that illegal immigration is connected with new patterns of organized crime, even if the overall crime rate is similar.