True, but under the standard rules of English word formation, irregardless contains a double negative in the prefix. Libs have bastardized the Constitution, our culture, and our language quite enough, thank you.
Oh, you're quite correct on that score. Personally I avoid that usage, since it's not only a double negative, it's not an effective positive, since it is taken to mean exactly the same thing as "regardless". So I have always preferred "regardless". In fact, for most of my 60 years I've considered "irregardless" flat-out incorrect; a non-word. I was at first shocked to see it get accepted.
Then I thought about "flammable" and "inflammable", and a few other examples, and decided to lighten up about it. Hence my tongue-in-cheek mention of a campaign to consider "irregardless" standard.