It is possible that most of those accusations against those casinos is true, even if all is not true, majority of it is true. Some non reputable casinos might have indeed scammed those guys that create the scam accusation topics while some of those accusations are also a false accusations which was the fault of the gambler and not the casino mentioned. If any reputable casino on this community is falsely accused, they will definitely respond to clear their name or their representative will likely respond.
Do you visit frequently on scam accusation board? Most of the scam accusation there is against reputable casino which ended up as garbage thread after failure of providing evidence.
Most of the accusations in the forum against casino is hoax since those users is just using the forum to take shield on hiding their ToS violation on the casino. Playing victim is very popular on that board that makes it very hard to support or follow new complaints especially if its involved sudden account freeze since this case usually incorporates violation of ToS once the casino reps clear their name by providing evidence.