I mean who wouldn't have realistically accepted literally billions of dollars to sell an app people willingly install on their phones? Ethics is all relative.
Were they profitable before? Were the controlling parties financially comfortable?
If my company is profitable (or has revenue growth and is likely to become profitable) and a scummy company wants to buy it, I'm going to say no.
Hard as it may be for some of the HN/VC crowd to believe, but there are people out there who start companies with their own money, because they believe in something. At no point does "find some fat megacorp to buy us our" enter the game plan.