Something to try next time - it might not always work, but worth a shot: when you've copied the text out of the email, paste it first into a PLAIN .txt file. So this means use e.g. Notepad, NOT MS Word or similar. Then copy the text out of the .txt file and into the forum.
Since .txt does not allow any kind of formatting (bold, italics, different fonts, different sizes, etc.), it doesn't recognize any either, so in theory the formatting information gets "pruned off" the text when you pass it through Notepad or similar, which stops the next program you paste it into from trying to reproduce any hidden formatting info like tags.
Of course if for whatever reason the tags actually show up as text IN the .txt file then you'll still have to take them out yourself, but that would be an odd thing to have happen!