Do you not notice the circularity of your reasoning here?

Also I didn't say incompetent, I said "not very". More competent researchers make journal rep only a very small factor, and it is not via the "high rep = more trustworthy" direction (which is the bad heuristic), it is "pay-to-publish journals = not trustworthy" (better heuristic).

Once you have ruled out a publication being in a trash journal, reputation is only a very minor factor in consideration, and methodological and substantive issues are what matter.

It all depends on whether the paper fits the journal. Minor journals serve a useful service as a repository for minor results. And minor results are still worth publishing because they might provide a detail or technique later needed for a major result. The thing to be wary of is when you see a stunning result that should really be in _Nature_ or _Science_ in some minor journal. Why isn't it? Was it submitted there first and rejected? It would be nice if the history of a manuscript (and its peer review) stayed with a manuscript so you could see if the authors really corrected problems brought up by peer review or were just spamming journals with a flawed manuscript until they found one that published it.

Agree with all this. Once you've filtered / made decisions of quality based on the more substantive criteria, journal reputation can provide useful additional information / context. The case you mentioned is a good example.

There is no reasoning. I gave you a statement of fact:

I have personally seen highly talented and successful researchers use the heuristic of journal quality when looking at the state of their field. These people are highly competent by any standard. If you want to play word games with negation you could say they are not not very competent.