A not so gentle move. But we have the right to party without ads, so there is a way for now.
Add this to the Disable Filter List:
And your Tweet-Button is visible again after reloading the site. Bam!
And right when I wrote this post, it appears to be solved!
At least in BetaFish Adblock. If you still have that problem, you can do as mentioned above and you're ad-free and ready for tweet. Or you could use Google+. The ad-free land.