Agreed. Having worked in both the public and private sector I’m wary of any government/corporate conspiracy theories because in most cases it requires an implausible level of competence from the parties involved.
Taking it one step further, there is no external conspiracy either, in the sense of BPS proponents getting together in a smoke-filled room to agree to fake evidence that ME/CFS is psychosomatic and portray all patients as psychotic if they complain about the science used. IMHO, the truth is far more mundane: they had a theory based on some not-great reasoning, got a lot of money to test it, then realising that a negative result would be damaging to their careers (and most likely still really believing in their theory), they massaged the analysis to give a better looking result. Something that happens very regularly across different fields of science.
My guess (and it is a guess) is that some of that field did receive a small* amount of abuse - and when the media (aided and abetted by SMC) turned it into a far more simplistic 'all critics of our work are anti-science and abusive' there was little incentive to correct that view because it had raised profiles and reputations amongst people not familiar with the work, and headed off hard questions around methdology. Again, no actual conspiracy to portray ME/CFS patients as mad, just a series of events accompanied by the kind of moral compromises that are common (not necessarily excusable) to many ambitious types as they try and ascend the career ladder. After all, it would take a lot of courage to stand up and say 'hang on, many of these patients aren't abusive at all and are raising valid problems with my work'. Easier to tell everyone, and oneself, that any criticism is just because patients don't want to accept they're mentally ill.
*My use of 'small' does not imply excusing any abuse if it did occur, more a comparison of the ratio of actual abusive messages received against just trenchant criticism of their work - furthermore, if anybody is abusive to a BPS proponent it actively harms the rest of us.