Put more plainly: just because you scanlate various works and our often our only source of said works does not mean that we, the readers, or various sites must bow down and prostrate ourselves before you as though you were gods.
if you think that you receive too little love for what you do, then note that every single download of a chapter that someone follows comes with his or her unsaid thanks. if people didn't like you or didn't appreciate what you did, then they would not download your work.
Why watermark though? Why not let other people enjoy your scanslation unmarked by putting a small line at the bottom of each page showing where it came from? People wouldn't go through the effort of removing your hideous watermarks and people who were interested in who scanned and translated it could see at the bottom of each page.And if what you want is to get more people to go to your site to get ad revenue, why not make it so you don't release a chapter until your site has been viewed a certain number of times since the last release?
People are getting too used to my all-over-the-page-watermark-.-I should exaggerate it a bit more...