Isn’t the whole al tarbeh issue the opinion of a specific Tannah ?(maybe I am mistaken, but that’s what’s I have in my memory bank).
If I am not mistaken, however, and the phrase was uttered by one rov, it is not necessarily halacha, but rather, his personal hashkafa. If that is the case, we are not bound by someone else’s personal hashkafa regarding something being “better to do or not do.” We are bound by what Hashem tells us we have to do or not do.