Trump has been the thought leader for the conservative movement
No he hasn't been the thought leader for anything other than the Democratic party who spend all their time addressing his endless stream of meaningless self-aggrandizing propaganda.
Democrats would support free access to vaccinations (since it is and should be mandatory) and a free breakfast and lunch for those kids.
They haven't delivered it. Jimmy Carter promised universal health care. As has every democratic candidate for president since. Some of them won. None of them delivered. They all blamed the Republicans.
He was for the covid shot when he was president then exploited fear about it once he was out.
Did he? That was certainly the message of antt-Trumpers. And it certainly reached his core of supporters since their enemies were repeating it over and over. Do you think that message helped or hurt?
Trumps primary messengers have always been his enemies. He says something stupid and they repeat it over and over until it becomes the truth. Can you imagine that the anti-Trumpers would have opposed vaccines if Biden had attacked them as having been rushed into production to help Trump get elected? Not likely. Or if he had praised Trump for his "warp speed" program to produce them? Not likely.
Lets be clear. Trump is an egotistical megalomaniac. He has no ideology other than personal aggrandizement. And his best allies in that effort are the anti-Trumpers that keep him at the center of attention. All anyone really knew about Harris was that she was "not Trump". Because that's all they saw she talked about.
They ain't fringe no more.
Yes, they are. Most parents are getting their kids vaccinated. There is no doubt that all the attention paid to anti-vaxxers has raised questions among a lot more parents. But who shined the spotlight on them? The anti-Trumpers for whom all things are Trump. When Bobby Kennedy says he supports measles vaccinations the first thing out of the anti-Trumpers mouth is to repeat his earlier anti-vaxxer rhetoric. Note comments above. And here you are defending the message against measles vaccination as "not fringe".