I actually learn the opposite from that story; That no one ELSE (other then the persons own Rav) has the right to judge them and decide what level ‘they think’ he is on.
Also, if any Rav paskens that even if two things are permitted, but that when both are easily available, that one should use the “more machmir (for lack of better terminology)” choice then obviously one who holds on that level even when it is a bit less easy to do so, is not being arrogant in holding by “high levels” that he has no business thinking he is on.
If that were the case, the Rabbonnim would have warned against it and certainly none ever did, regarding Cholov Yisroael, that I have heard about.
I further think, that if some Rav had given such a warning, someone would have posted it on this thread, by now.