There's a difference. When servers started allowing nicks longer than 9 characters they made things less restrictive, but not following it in this case is making it more restrictive. Perhaps a friend using another client has a long channel name for some reason, why should I be prevented from joining it just because I'm using mIRC? Answer - I shouldn't.
What makes you so against having mIRC capable of using all the functions of the IRC servers it can connect to? Perhaps it's not the most important thing in the world, but there is no reason to be against it.
IMO the fact that that RFC is so old (the first RFC on IRC) means that it should be supported as a minimum, adding improvements as you go, not pointless restrictions.
Of course you could argue that the newer RFC2812 says that channels should be a maximum of 50 characters long, I presume you will be in favour of that now?
