There is a crackdown on falsely promoting junk food as healthy or promoting it to people who don't know better (namely children). Maybe not on YouTube, but in various countries' legislation.

http://news.bbc.co.uk/2/hi/health/6154600.stm

https://www.wsj.com/articles/SB106919100053167300

https://publications.parliament.uk/pa/cm200304/cmbills/110/0... (Section 3)

It's not really a fair comparison, though. The main issue with anti-vaccination content is dangerous misinformation, not simply promoting something harmful. The other issue is that the people who fall for this content aren't usually the ones who get hurt, their innocent children are. It would only be a fair comparison if there were a large movement of very influential, powerful, and famous people posting "vegetables cause autism, and Burger King cures it" videos out there to hundreds of millions of viewers and a boom in child obesity tied directly to parents viewing them.

Yes but the line between good and bad food is not as clear as the difference between vax and no-vax. Moreover some countries (eg France) already have restrictions on junk food advertising.

Disproportional comparison that misses the point entirely.

A major difference is not vaccinating yourself can cause the death of others.

How you encourage healthy eating and moderation is also a very complex topic in comparison. Vaccination is a much more binary choice (you vaccinate or you don't), and is highly effective.