Hi,
I really don't get how everyone is putting a "liked my post? donate!" in their signature. I mean, come on, wtf? Now you expect me to pay you because you voluntarily decided to express an opinion and it wasn't total crap?
What's with the greed, dude...
Seriously, how much do people expect to make this way? A dollar a week? 1.20$?
Up to here, you had a somewhat valid 'complaint' - although I still think you're overreacting (noone is expecting you to pay him, you are just given the option in the odd event that you may want to donate something to a user).
I propose an unconditional, unlimited ban for everbody having a bitcoin address in their signature!
Here it gets ridiculous.
Like, seriously, ridiculous. Ban someone for a bitcoin address in their forum signature? What's next? Ban people for having a megahash/sec tag? Ban people for saying something about Satoshi? Ban people for linking to their Bitcoin-related service without having a 'premium' forum subscription (as some non-Bitcoin forums do)?
Live and let live. Noone is forcing you to do anything. Noone is forcing you to send them money. Noone is 'begging' - they are simply providing a Bitcoin address for those who wish to donate to someone for whatever reason.
Disclaimer: one of the things I actually like most about the Bitcoin economy is that it's very donation-driven, compared to the 'regular' economy. People set up services, and simply accept donations instead of charging a flat fee of everyone. I consider donation-based services or products as 'voluntary payment' (the Humble Bundle works in a similar way), something I absolutely support, and actually use myself to pay for all of my expenses.