Being to Dubai does not make a sliver of a difference when confirming whether they use "slavery" or not. I have been to Dubai multiple times and haven't seen anything bad going on there, but why should I be seeing those things anyway? slavery and such do not occur around those developed parts International workers are being overused there and when they try to return to their country, their visas and whatnot get denied as shown in multiple documentaries. Just admit Dubai and countries in the Middle East have problems, but don't make a fool out of yourself by saying "oh but you haven't been there". I love Dubai and multiple countries in the Middle East, but this doesn't mean just because you like something you don't acknowledge its problems.
Every country has its problems but that doesn't mean it should lead us to having a bad opinion on it. Just acknowledge it and move on its as simple as that instead of creating a whole argument or ragebaiting, it doesn't not prove your point and is not worthwhile.