Survival of the fittest is a biological mechanism that's special in nature (species-ial: not really, really great). Attempts to combine it with social, cultural or economic theory are fundamentally flawed.
@Dave70 : while I've always been against shutting down opposing voices (even if sometimes I personally need to walk away), campaigns like that are not shutting down free speech. If leaflets were siezed, books burned, authors imprisoned, speeches censored or programs refused broadcast and punitive measures carried out by a state authority, then the concept of free speech/freedom of expression would be relevant. A company should be able to make their own ethical choices
(as should a religious organisation on the other side of the debate). Both sides will get heard, let's not get too dramatic.