It’s not really our bug.
I agree that it’s not your fault that the world wide web’s addressing system works the way it does. But fixing this in Obsidian doesn’t mean taking responsibility for that. It only means taking responsibility for your UX.
Dots at the end of URLs are valid.
Not in practice. Google Docs, LibreOffice, your own forum software, and other programs make sure that periods at the end of URLs aren’t part of URLs. Here:
Carroll, Glenn R., and Dennis Ray Wheaton. “Donn, Vic and Tiki Bar Authenticity.” Consumption Markets & Culture 22, no. 2 (March 4, 2019): 157–82. https://doi.org/10/ggw56p.
I urge you to copy and paste that citation in other programs to see for yourself how many other developers decided to make sure that periods at the end of URLs don’t become part of URLs. You don’t have to do anything just because everybody else is, but I think it’s at least valuable to consider the possibility that there’s often a reason.
Also, I doubt they consider it “their” bug for the same reasons you don’t consider it yours. They nonetheless choose to fix it in their respective programs for UX reasons.
I suggest you contact Zotero’s devs and made them aware of this issue and/or define a custom Chicago style within Zotero where you fix this issue yourself.
Zotero is doing exactly what it should: providing a correct citation. If they messed with it, then it would no longer be correct. If they did anything to (somehow) make it so that periods at the end of citations don’t become part of URLs in Obsidian, then it would no longer work correctly with any other program.
And if I defined a “custom Chicago style,” then it would no longer be a correct Chicago style citation.
I’ll go away now. I’m sorry for being such a pain.