There is a difference between stating your thoughts/opinions then people being offended vs saying something that you know is offensive (which the headline indicates is the case) then people being offended. The former may challenge beliefs, while the latter likely lacks that line of thought. You may be mischaracterizing all instances of offense as challenging ideas when some may just be hurtful for the sake of being hurtful.
I’m not sure why you think *all *left-wing people don’t care about being called names, or why that would be a trait of left-wing people specifically. It just seems like an overly generalized statement about a group based on your personal experience.