I brought this up with a writer from an accessibility perspective, and they were very adamant (and a bit of an arse) that I am wrong, and on the web every sentence should be a new line. I eventually gave up on them. As they say don't throw pearls in front of pigs.

A paragraph = a new thought. Every sentence cannot be a new thought. This is stuff we learn by 4th grade. Not sure when some writers stopped their education, but clearly, they need a refresher on primary school stuff.