Would the author feel the same if git had used MD5 instead of SHA-1?
They address this very theoretical. In short: Yes. Which makes sense if you don't treat the hash as a form of security against malice, especially in the case of attacks that are already impractical, which is the entire thrust of the article.
The hash isn't the security, the distribution is.
https://lore.kernel.org/git/Pine.LNX.4.58.0504291221250.1890...
As linked by another commenter in this thread, Linus worked out years ago that even if someone inserted a malicious object into the kernel repo, it would at best be a nuisance and not a major concern.
Follow the ethos of the quote master!
> We could be using MD5 and it would honestly probably be just fine.
I do actually literally write in this that if it was MD5 it also would not be a problem.