Indeed, and I have no problems agreeing with you on *dūmas. But you are the one who pointed out this fact; so I feel you should be in the references section of that page. If you don't want it to be under your User page, make it an appendix page: "Proto-Baltic as Proto-Balto-Slavic" or "Proto-Balto-Slavic correspondondences" and write a short paper on this topic. (R. Kim's paper is probably a good basis for it.) And then refer to it in the references section. (Since this is an independent contribution, I feel it should be in your name. If it were my work, my opinion, I would be honored to have it linked to my user page as the author. But if for some reason you don't want to be "the author", then let it be an anonymous Wiktionary Appendix page -- but one to which one can link in the references section.)
When this is done, I will have no problem linking to *dūmas from the etymology section of Latvian dūmi. (That's what I did in sniegs, for instance.) Because then anyone who is interested in this etymology will be able to know where it comes from. This increases accuracy and reliability/validity, and thereby trust.
See, for instance, what happened with bērzs. Ivan Štanbuk had added a PBS etymon. At first I thought it was unsourced, so I reverted it; then I realized he had sourced it, only he hadn't included the sources in the etymology section itself with the <ref> </ref> markers; rather, he added them under ===References=== as simple text. So I reverted my own edit, putting the PBS etymon back (and added Štanbuk's sources in the appropriate places with the <ref> </ref> markers).
I'm not anti-PBS; but since PBS reconstructions are new, I just want accuracy and consistency, in order to foster trust.