Well I don't really use Trello, though I tried it for a while (wasn't my cup of tea). But the difference between WhatsApp and YouTube and Trello is that the latter is used by a different crowd than the former which is more conscious of and partial to their tools. Thus if Atlassian messed up Trello they'd certainly create lots of bias against the company as a whole in the Trello community, but that can't be said for WhatsApp or YouTube, where the majority of the users don't even care which company owns these services (I guess most wouldn't even know), let alone hating that company for changes to acquired products.