I think we will agree more than not. And so you have a better idea of my thoughts:
1) Science is the gold standard when it is allowed to work properly. But with PD external forces and conditions have to be dealt with.
2) One is the force of money. We represent about five billion dollars a year. To pretend that that much cash does not impact things would be naive. It is a factor at every level, too. From my decision between brand and generic. To a scientist's calculation of how to structure a grant proposal. To a department head's decisions that influence a subordinate's tenure. To public funding allocation at NIH. To Big Pharma boardrooms where the discussion is on duty to shareholders, not to welfare of the patient. To the multi-Orgs where staff's first duty is to raise funding for their own salary each year. Each level influences the science.
3) Another is the force of the marginalization of the patient. With few exceptions, nobody cares what we think and they darn well don't want to hear why we think they are wrong. And as individuals, our voices grow weaker each day.
4) Another is the force of academic conformity. Nobody gets tenure because they discover that a blamed foot injury really is the cause of PD. Truth would be irrelevant.
5) Another is the sheer success of science in gathering data over the last forty years coupled with the failure to interpret it. It is like those NASA warehouses of precious lunar orbital data from the 60s left to rot.
6) Finally, there is the fact that the current orthodoxy on PD is dead wrong and time and money are being wasted. PD is not even a neurological disease! It is an immune-endocrine disorder that, with a little help from the GI system, damages the nervous system under the onslaught of environmental insult mediated by genetics and epigenetics. IMHO, of course.

You see why they don't invite me to their parties.
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