Designers: What do you do when you find a forum that removed your copyright?

[voronv]

It's down to theme designer to choose if to add a copyright line or not. just like it's your choice to use it or not.
Which hopefully would be not. (for those who don't respect it)

No objection to above said.

But if one side wants to save money on paid advertisements through(mis)using the public domain sites then the other side's effort to cut expenses looks very much justified.

And, BTW, I have an answer to that person with no manners : where else to post your works if you want to sell it? -Try eBay.

Ecommerce normally should be prohibited in any form on open source and public domain sites. If only I'm not awared and you make generous donations to this site and its founders let you do what you do because of this.