Discriminate against them? No.
Which is of course another problem of the religion tolerance issue. It's so very one sided. As an atheist you have to tolerate religion but as a follower of a religion you don't have to tolerate the reverse. For example recently here, in the UK, there was an advertising campaign someone ran saying, rather tamely, "There probably is no god. Now stop worrying and enjoy life". This provoked an unreasonably amount of outcry among lots of the religious group, however the wording is no where near as aggressive as that upon boards outside churches which for the most part state you are evil unless you worship there. Seems very one sided to me, freedom of speech should sacrosanct (not that any country actually has that, but I live in hope one will)
I'm not entirely sure what you're trying to say. Why does one not have to tolerate atheism as a religious person? I tolerate atheism just fine. If somebody doesn't try to force it on me, then fine. That campaign wouldn't really bother me at all. People can express themselves if they want to, as long as it's not causing any harm, or trying to force their views on other people. Really, it's just a problem that many religions that have an afterlife (examples include Christianity) tend to condemn anybody outside of that particular religion, or anybody inside that religion that does something against it (homosexuality and many Christian groups, for example).
Personally, I believe in reincarnation, so whether or not you follow the religion doesn't matter. I have about the same attitude towards other religions that Atheism does. Basically, it doesn't matter whether you follow the religion or not, the outcome is all the same; it's just that following the religion can help you see the "truth" better, and in some cases save you some time. The difference is that Atheism tends to say that religion as a whole has no point, while I say that just blindly following the religion has no point; you have to discover the "truth" for yourself.
And in case anybody is wondering, yes, I am "hiding" my specific religion on purpose. I'd rather keep it to myself, because it's tied to my other beliefs, most of which are, well, looked down upon by most. (No I am not a Satanist or something ridiculous like that, though my religion is occasionally confused with it by some
)