A swear filter NEEDs to be internal to irc, or mirc scripting needs the ability to modify incoming text before it gets to your screen. Otherwise you cant properly script your own swear filter.

The majority of users are chatters.
A flood kicker isnt used by chatters. its used by channel owners. Most of that functionality already exists with eggdrop scripts, and ircd's.

irc op commands dont need to be inbuilt. They are external to the client and are easily scripted. Im suggesting a swear filter to be inbuilt because its currently not possible (to my knowledge) to modify incoming text without halting the text and /echo'ing it to your screen.

User mode +G (on unreal ircd) does not filter channel swearing.
Channel mode +G does filter channel swearing, but that affects the entire channel, and not just the end-user. filtering done on an ircd level increases the servers workload. It makes alot more sense to block it on the clients side.

It isnt a difficult task to add a swear filter to mirc. It doesnt have to be used by the majority to make it feasible to have scripted. It just needs to be something that a large number of people find necessary to use the product.

Take net nanny for instance. Would you tell parents to not use the internet because theres porn sites on the internet? No, you purchase software that has the ability to block such sites.
I personally dont know anyone who has net nanny, but im sure theres alot of people that use it. But it still exists. Because people have the need for it.
Same goes for voice recognition software. Its not used by the majority, but its still widely used. It has a purpose. And its essential for alot of people to use mirc.

I am just surprised that it doesnt already exist considering the large number of mirc users, and the fact that its been out for over 10 years.