I've provided a very specific definition of what good OOP requires so it's not fair to suggest that my argument is pointing to some vague characteristics or is evasive.
I can look at any project's code and assign it a score in terms of cohesion and coupling of the classes/modules/components. Other people who are experienced with OOP can look at the same code and they will come up with a similar score.
The point of "No True Scotsman" is that you have your own definition of high quality OOP, which is not universal. Maybe yours is the right way of doing things, IDK. But I think others would probably prefer different definitions. For a lot of people, this variation in opinion of how OOP should be used can lead toward a conclusion that OOP in and of itself is a confusing concept and difficult to get "right".
Some people, myself included, just try to avoid this complication altogether, by separating data from logic.
FP solves some issues but simultaneously introduces a new set of issues which creates new 'No true Scotsman' debates around ways to address those new issues... It's like the joke that there were too many competing standards and so somebody decided to invent a new standard to make all the other standards redundant... The net result of this is that we end up with n + 1 competing standards.
IMO, the biggest problem I often see with FP code bases is poor separations of concerns which leads to spaghetti code which is hard to read and maintain. When some state is not co-located the logic which is supposed to be operating on it, you're already throwing high cohesion out the window... And when you do that, it makes is harder to separate the responsibilities of different components because there is no clear ownership relationship between the logic and various bits of state... With FP state can end up being mutated all over the place and it's hard to know who did what.
I can look at any project's code and assign it a score in terms of cohesion and coupling of the classes/modules/components. Other people who are experienced with OOP can look at the same code and they will come up with a similar score.