Not the best fixes ever, but... they're better than nothing.
Firefox users who are not happy with the crossposting to Facebook and Twitter, there is an option.
Go
here and install the Greasemonkey addon. (Enable, then restart Firefox.) Then go
here and install the script. Greasemonkey will automatically install. Works on all comments pages, so you can't accidentally crosspost.
To hide it from your own journal regardless of which browser you're using, so people can't comment and repost, do this:
1. Go to Journal > Journal Style
2. Go to Customize your theme
3. Go to Custom CSS
4a. Copy and paste
.b-repost-item {display:none}(make sure you're just getting the bolded text) into the Custom stylesheet
b. You might have to change one or more of the Yes/No boxes above the stylesheet in order to get it to work
5. Save changes
***Important to note: This will only work if people are viewing your journal or comm in your style. If they're viewing it in their style or light mode, it'll still show up. This just hides the feature, so if their default setting is to NOT automatically post, they won't be able to post. It also runs the risk where if someone has their default setting to automatically post, they won't be able to choose NOT to post.
((I picked up this code and instructions from someone who picked it up from someone else who... I honestly don't know how often it's been passed around. Credit where credit is due.))