I think this rollback is in error

Unless the etymology entry for блохá, too, is wrong.

What was the basis for your reversion?

It's already listed on the Proto-Slavic page.

I don't understand the logic here. After all, French puce is already listed in the entry for Latin pulex, but it shows up in this article. And English flea is already listed in the entry for Old English fleah, but it shows up in this article.

I guess your aim is to avoid redundancy, by limiting mention of the origin of Russian блоха to a single occurrence in Wiktionary? But to my way of thinking, that comes at a very high cost. The reader who is not intimately familiar with the way Wiktionary editors structure things can easily end up ill informed. Why, after all—he might ask—do descendants in such modern languages as Armenian, Lithuanian, Latvian, Dutch, English, German, Greek, Pashto, French, Italian, Portuguese, and Spanish show up in this article, but none for Russian? He might easily conclude that the Russian word for "flea" is something derived from someplace other than the Proto-Slavic (labeled in this article as "Slavic," which itself is a potential source of confusion). And likewise for the modern Polish word.