Even the fact that those crates are old ones (around 6 to 7 years old), they are not marked as yanked in the index.
I even try from add them as dependencies in a dummy crate and I still have that 403 HTTP response code.
And anyway, I do not need them, but, I am just being curious here
So here's my question, why those crates can't be downloaded from crates.io?
Maybe there was a request to delete them because they accidentally contained data that is not supposed to be public (could be anything from accidental copyright infringement, trademark issues, personal/private/sensitive data, etc.). Returning a 403 might be a possible thing to do, but maybe a 410 would be better.
Anyway, it's just a guess. Not sure why these crates are not available.