The largest protests in the U.S. are anti-abortionists

But do you hear about them? NO! Because the media never covers them. Yet, they cover a dozen or so people at Biden’s dementia speeches.
650,000 in 2013. Probably more, since Wikipedia is affiliated with Soros and Wiki’s notorious for being biased.

Between 2003 and 2012 the marches drew crowds estimated in the hundreds of thousands.[11][12][13] According to organizers, the 2011 event was attended by 400,000.[14][13][15][16] In 2013, Life advocates estimated the march drew 650,000.[17] As with all large crowd estimates, the generated number of attendees reported differ, with some sources indicating a figure in the tens of thousands to low six figures. WIKI