I think that if you're really bothered by them being religious then just don't buy the products?
I personally refuse to buy Sanitarium (although if I'm somewhere like a party and they provide vegan products by Sanitarium I won't just refuse to eat them) and yeah some people get upset but it's my decision and it's not going to change any time soon. If you don't like them then just refuse to give them your money. It's pretty simple.
There are plenty of other non-religious companies offering similar products.
Check these brands out:
Fry's
Redwood
Tofutti
Quorn
Linda McCartney
Well, Tofutti isn't owned by a church like Sanitarium is, but it was founded and is owned by an Orthodox Jewish man specifically for the purpose to be consumed with meat (as meat and dairy cannot be consumed together under the laws of kosher). Many people think it is vegan and it is most popular with vegans but the actual original intention of the product was to be able to consume with meat. http://www.tofutti.com/kosher/ and http://www.dailyfinance.com/2013/07/03/the-strange-way-he-got-rich-turning-tofu-into-ice-cream/
Personally, I do still buy Tofutti as it is a fantastic alternative to dairy, and it is its own product, but I suspect by buying it I am still in a roundabout way supporting the meat/dairy industry and the kosher slaughter industry by doing so.
I did not realise that about Linda McCartney and I am disappointed!!!
Then again so many companies own each other almost everything seems to go back to the meat/dairy industry one way or another.
I guess that is why I have a soft spot for SDAs - weird cult perhaps, but it will never go to meat.