I have seen many studies where they say that qualified investigators can have access to the data if they sign lots of forms, agree to collaborate with (not just acknowledge) the original authors, and wait six months for this all to be approved. I expect that I would be approved if I did all this, but it's not worth it. In some cases I suspect the study is flawed, but debunking it months later would be a lot of work for little return. In other cases, the study
looks OK, but without ready access to the data to confirm this (and perhaps get more information with a more sophisticated analysis), it's really pretty much worthless.
Yes, worthless. As in no one should put any weight on such unconfirmable "evidence". It's just wasted effort by the investigators, who piddled away their time (and their funding agency's money) because they're not willing to release the data.
These are not studies where one would need 3 months to just understand what the variable names mean - perhaps the data was extracted from such a huge database, and perhaps there are issues with how that was done, but there are also quite possibly issues with what they did afterwards, which can be examined separately.
Comments by unqualified people on twitter are a fact of life. You can't get rid of them without also eliminating comments that reveal mistakes (even fraud) in what superficially seems like authoritative research. Your judgement that such uninformed comments are intentional lies is probably untrue in most cases.