I don’t remember any other President in my lifetime holding regular rallies during their presidency. I'm open to being corrected on that though.
Well the Hatch Act used to keep more of a lid on that stuff than is the case now. Trump is exempt from it and so is Pence, but let's face it, some of the people who help him put these things together are not.
Past legal restrictions, the fact that Trump has treated his entire presidency like one unending campaign against "the other party" when he's taking a breather from tweeting vengeance on people he just regards as personal enemies (anyone who has crossed him, ever) is at the very least unseemly and a gross violation of past norms for our presidents.
Trump's failure in meeting a duty to differentiate his public remarks as a President, a partisan or just a citizen with a personal opinion certainly does nothing to shore up domestic or international understanding of the American presidency as officially having "all Americans" as constituents. That half-opens the door for any American president to treat the presidency itself as nothing more than part of "to the victor, the spoils" in a political contest.
Along with Trump's blatant scofflaw tendencies, his use of the WH bully pulpit as a permanent campaign platform creates an illusion that rule of law applies to underlings, not an American president.
How can it even matter any more if a future president picks up a smartphone and tweets a blatantly partisan remark from the WH? Trump has done it for four years straight.
To his supporters, Trump's public appearances and tweets may always have seemed part of one big ongoing rally... with the exception of those times he has issued any kind of walkback under some duress. And at that he's always managed to do those with a kinda wink wink that translates to "you know why I have to say this at the moment, right?" -- and he was pulling that stuff even during his campaigns in 2016 when dissing then well known leaders of the Republican party including John McCain and Paul Ryan, and then having to "apologize" and say he fully supported them.
He went out there and did those scripts the RNC handed him that summer as if he were a kid forced to write "I will not throw chalk at the back of the teacher's head" 100 times on the blackboard after school. And it was intentional that he came off that way. And it's to our shame that such behavior might well have been part of why some Americans voted for him.
We need better grade school civics and history lessons. Learning them as adults in the past four years is costing this country an unknown price, one that I hope we can actually pay and still have a country people want to live in.