Okay. This is a side-effect of hard-coding the font size for Launchpad as a whole, to 10pt (13.3px at 96dpi), instead of leaving it as the default. We then override that to {font-family: monospace} for bug descriptions and comments, resulting in monospace 10pt, instead of whatever your default monospace size is, which is likely smaller than 10pt.
We could hard-code a smaller monospace size, but font preferences vary widely, so we could worsen things for more people than we improve them. I think the best solution here is to set Launchpad overall to use your default font size.
Okay. This is a side-effect of hard-coding the font size for Launchpad as a whole, to 10pt (13.3px at 96dpi), instead of leaving it as the default. We then override that to {font-family: monospace} for bug descriptions and comments, resulting in monospace 10pt, instead of whatever your default monospace size is, which is likely smaller than 10pt.
We could hard-code a smaller monospace size, but font preferences vary widely, so we could worsen things for more people than we improve them. I think the best solution here is to set Launchpad overall to use your default font size.