It very easy to spot shady companies on Reddit, Twitter, and other social media, what they do is to create a promotion and then limit the comments to only the ones they approve and that is a violation of the right of the followers to drop their honest reviews about their services.
1xbits have a bad reputation and they are aware of it that if they allow users to comment on their promotion threads there will receive negative comments and for that, they will limit the comments their receive.
Sometimes it is not that easy, though.
If the company is big enough and is very willing to further keep their facade of legitimacy, they could be as far as keeping the comments enabled, but have an army of bots leaving customized positive reviews and comments, so the negative ones would be way harder to find to any newcomer trying to do their on research, and unfortunately, in the advance of artificial intelligence, it may become more difficult in the future to tell whether a message is actually a human leaving a good review or a machine...