As I said, totally disabling them might be a bit too drastic. But I don't complain about the size (in bytes) of images in signatures, which I still find a bit annoying sometimes even with broadband by the way, but about the visible size of some signatures. They are obtrusive and distracting.
Sure, I can disable "show sigs", but the majority of lurkers can't. They have to wade through lots of junk that is interesting once or maybe twice, but otherwise irritating. If you come to a forum to find useful information or just for a fun discussion, then all the superfluous extra bits can be quite tiresome, to put it mildly.
Besides, I don't have anything against signatures in general, actually I do like them for what they are, just not when they are "louder" than the text that should matter. I would like to enable them, but their current neon-blinking-popup-advertisement like nature prevents me from doing so.