Including less-than-ideal data in a broader analysis is completely fine as long as you're aware of the data quality issues and adjust your weights accordingly. IMO Alexander does a pretty good job of this - I recall many occasions where his writing references a study while also caveating that reference because of a limited sample size or a slightly implausible effect size or some other qualm.

There's a world of difference between trying to make sense of a topic when none of the available data is all that great, and outright fabricating data to make a name for yourself.