It's not just Trump.  The toxicity has been growing since Mitchell openly stated that the primary goal of the Republicans was to ensure that Obama would be a one-term president.  Then came the rise of the so-called Tea Party....
It often seems to me that those who want to "tell it like it is" are merely looking for an excuse to be (at the very least) rude, or to demean and disparage others who, for one reason or another are not the "right kind" of people.  One problem with this is that any one of us can become the "wrong kind", depending on the circumstances.