I think that's both a very privileged position and an unhelpfully narrow view of how insults can work - slurs for example - and it ignores all aspects of social power.
A cis person usong the t-slur against a trans person/a straight person using the f-slur at a gay person/a white person using the n-slur etc.
is doing far more than 'telling the truth'.
And how we viscerally react to a threat - like a random man calling me a whore/bitch/slut etc. - is not merely a choice.
We can't just choose to ignore a world full of injustice, the hate and the threats of violence that come to us through insults.
If you're only talking about someone calling people baldy four-eyes numpty or whatever, that's something else.
The solution to injustice isn't having thicker skins.