Ugh, this topics are rather silly because it shows people don't really understand memory management.
Having a bunch of free RAM is bad because it means it's not being used. A program is only a "RAM hog" if it's holding onto a bunch of RAM and isn't doing anything with it. The last part is important, because web browsers will cache previously loaded data so in order to make your web browser seem to run faster. Remember you may load hundreds of web pages which are stored in cache so Safari doesn't download those images each and every time.
The problem isn't programs using a lot of RAM, but not freeing it up for other program to use when it's closed (a memory leak).
Also, keep in mind that there's also "inactive" memory, which is data stored in memory from a closed program which can be quickly reused again if the program were to be re-opened.