There have been meta discussions on this topic and there really isn’t a clear answer. It quickly devolves into “how do you define NSFW”. And there are good arguments for a broad variety of answers there.
Looking at OP’s particular kink as an example, one argument is that, even though you’re showing completely clothed people, you probably shouldn’t be showing pictures of sexy girls wearing watches on your work computer. It isn’t porn, but I think your coworkers would quickly see that you are getting a sexual kick out of it regardless. on the other hand, most people consider this a porn instance. There are a lot of things that aren’t safe for work that really don’t fit with what most people consider the purpose of this instance (porn).
As I recall, the instance doesn’t prohibit SFW content. It’s just that people here aren’t looking for SFW content and a lot of them are going to downvote SFW content because they don’t want to see it. The instance could try to tell people not to downvote these posts, but that’s not going to do much to change behavior. While some people do follow such guidelines, most aren’t going to follow upvote/downvote guidelines and are going to vote as they wish.
It looks like an oddly worded way to ask a question to straight people. I think the first part of the title would work better as something like “Straight identifying people, have you ever…” or the question could have been asked more generally like “have you ever had a sexual experience that didn’t match with your sexual identity? How did it go?”