IMO, you should stop supporting Marriott if at all possible. Google "marriott tibet tweet" and choose your outlet of choice (less about the specific firing and more about censorship cowering sans transparent statement). I also like Nestle candy in general, but try not to eat it.
Marriott then fires the employee and releases a statement on twitter saying "We don’t support separatist groups that subvert the sovereignty and territorial integrity of China".
That hardly seems like a reason to stop supporting Marriott. What would you have wanted them to do differently?
Not let a government set their principles on what they can and can't do on Twitter. This is really simple. If they principally believe that they were wrong to like that tweet, then I disagree with their principles. If they were being pressured to react to it by a government, then I disagree with them cowering to any government about a liked tweet. Either way, they did wrong and they weren't very clear about what was requested by a country's government and what wasn't.
No different than Apple being forced to put icloud servers in control of non-Apple company in China...all you have to do is be transparent so I can disagree with your principles, unless your principles are money only, at which point I can disagree with that too. (and no, don't pretend like all of us with companies only care about money)
So, to answer the question, they should have ignored the request and been clear about what was asked of them. Since they didn't, they probably saved a lot of money even if they lost mine.
I put this in parentheses: "less about the specific firing and more about censorship cowering sans transparent statement". I disqualify establishments without principles in situations like this. Very simple. It's why I alluded to Nestle as a company too. The they-all-do-bad argument doesn't mean we can't exercise any judgement within.