I agreed with ab2 and Charlie basically 100% at first, but I've been thinking more about Olin's point. On the surface I disagreed at first, but as long as the actions are not stifling to either the community or the individual users then Olin is correct, especially in the specific use case provided here.
I thought ab2's assessment was great:
I postulate that the OB VTCs came from people who did not know much
about European long distance trails, and so it seemed OB to them.
However, a person knowledgable about European trails gave an objective
answer, backed up by pertinent information.
That sounds great, but that is hindsight. Couldn't that happen for most questions that are asked? We cannot know ahead of time, so that logic suggests that all we can do is sit and wait to see if an expert comes along who shows us that it's not really opinion based. How long do we wait? You can never be sure you're waiting long enough unless you wait forever.
That is not a problem with ab2's argument, nor with Charlie's nor Olin's... the problem there is with the mechanics of StackExchange within which we have to work.
Nonetheless, the mechanics of SE are what they are, so all we can do is decide how best to work around them and within them. While we must be able to use our own opinions, lest nobody ever act at all, I do agree that SE in general is way over-policed. TGO seems to be better than many others, but even here the policing can be annoying at times.
StackExchange strives to be the place where there are no tangles, no loose ends, just questions and answers within a hard set of rules and guidelines. However, no matter how robotic some people try to make it, I think this demonstrates that the answer is not straightforward...
There needs to be a balance. User1 needs to be able to act according to their opinion, User2 needs to be able to ask questions and get answers even if they don't conform perfectly to User1's ideas of the rules, and all while we likewise accommodate User3, User4, etc.. So Olin is not incorrect in his point, but despite being correct we need to balance our opinion very heavily with the desires, needs, and opinions of others. We need to err on the side of caution, otherwise the site is not as helpful to people as it could be.
For the example cases: #2 ab2 and Charlie were 100% correct about. At least from the title (I haven't clicked the link), it is completely not opinion based. For the provided case #1, this then begs how we should have handled it.
Should it have received no VTC and everyone give it the benefit of the doubt? Then what do we do if it receives no expert non-opinion answer, but possibly receives a bunch of opinionated ones and becomes a problem Q&A?
Should it have been closed? Then what happens when the expert comes along with the true and non-opinionated answer? Either we don't get it, because they silently move on, or they request it be re-opened for their answer. Is that a desirable route, closing because it looks at first like it should be closed and then re-opening later on when an expert informs us otherwise? That seems like a cumbersome process. Would it happen often?
Lots to think about. Maybe this is not a simple matter.