And completely misses the fact that the US has LOTS of free toilets--gas stations, state run rest stops, McDonald's and other fast food joints, Walmart/Target and other big box stores, pharmacy/drugstores, etc.

What has actually been asserted through dogwhistling is that "There are few free public restrooms where there are lots of homeless and/or drugs". That probably is true.

That tends to be cause and effect: an increase in homeless and/or drug users generally causes free toilets to shut down so as not to be an attractive nuisance.