The actual solution would be for HN to introduce a way to add quotes. Just having > in front of regular lines sucks - the many attempts at making quotes stand out more show that this is not just a single opinion. I "overload" monospaced because there is no proper option.
If you want quotes to stand out, italicize them. Again, everyone will know what you mean, and you won't break UX in a way that makes some readers more likely to ignore your comment because it's such a pain to read.
Italicizing is not a good solution for quotes IMHO.
I don't add the following links because that's where I got my opinion from, it's only in support. I came to my own opinion by reading a lot on the web :-)
In addition, only very few people in this forum use that method for large quotes, so without consulting a style guide, it seems to me most people feel that way.
Your options are to italicize, to introduce with a leading >, or to abuse monospace formatting in a way that breaks the user experience. Either of the former two is better than the latter, and my experience of several years on HN is that leading > is by far most common for quoting, but if abusing monospace formatting is the way you want to do it, then by all means abuse monospace formatting to your heart's content.
