That's a pretty extreme case and wonderfully framed to back up your assertion, but even it is kinda wrong IMHO.

Dating sites in particular tend to promote the values their clients hold. If it's a dating site where "wholesome" is the clients primary value then advertising on a porn website would be detrimental, however a company like adultfriendfinder benefits greatly from advertising on porn websites.

What I assumed we were talking about was actual big brands like McDonald's or Nike. They, unlike dating sites, tend not to be as dependent on their customers moral values and so context isn't as important.