[sophacles]

Of course not, don't be silly:

1. Saying a person founded a group is not an attack, insulting them is.

2. The relationship between a vaccine stance and an environmental stance is weak, if existent at all. The relationship of a political advocacy group and a media outlet is pretty strong - that is "i have something to say and the tools to say it loudly and widely" is a common pattern among those with the means (religions, wealthy folks, political fringe groups, etc). It's not ad-hominem to say "this new MLM Bernie Madoff is promoting is very similar to the ponzi scheme he was previously convicted of" either.

3. It's not ad-hominem to declare that a persons actions are consistent with their stated goals - it's not an attack, nor is it an attempt at discrediting (or supporting) their position. It is ad-hominem to say "unrelated opinions about vaccines discredit this environmental opinion".