>he’s the first person to run on the Republican ticket that shot back
It's hard to believe anybody believes this. I understand both sides always feel like the other side is always "worse" by essentially any metric, but first? The first Republican candidate to mock democrats or be shitty? You mean the most extreme, surely.
Also, "shot back" implies something comparable. Again - I don't really believe anybody thinks what Trump culture does is comparable to what either Republicans or Democrats have done to each other for decades.
If you mean it asymmetrically - as in the president "shooting back" not at the other presidents, but at the media and constituency of the opposite party, then in that context it makes even less sense. It was always the case that the media and online shitposters waged petty war against each other, while the presidents made rare jokes that were more diplomatic (on average...). It was always a gradient going up the chain - the people at the bottom saying the worst things, then the media in second place, then elected officials, then the president. But Republicans were always varyingly more extreme at all levels of that hierarchy. There was never a layer where the Democrats were shit-talking the Republicans in a way that the Republicans didn't match or exceed. So it doesn't make semantic sense to say that Trump "shot back" - what Trump did was pull the worst of those bottom bits straight up into the presidency, and all layers in between. The Democrats are "shooting back" by reactively getting more shit-talky at higher levels. Of course, that's not the right thing to do, but it's understandable, and they still don't come anywhere near Trumpism, qualitatively or quantitatively.