The MLA is dumb

I understand the need for rules of language, and of course that language changes over time, but it seems counter to the natural evolution of ideas to impose them prematurely. It's as though someone said from On High "Effective immediately, all humans will be tripeds." Never mind that every person who knows how to walk will have to relearn that most basic of skills, and that chaos would ensue. Orders must be followed because the Most High decreed that it be so. Of course, chaos never ensues, and people follow the rules to varying degrees, which once again calls into question the validity of it all. Why should we have arbitrary rules which are too complicated to know intuitively, yet too fluid to allowfor a societal learning curve?

What brought this on is that apparently you're not supposed to put two spaces after a period anymore. Why change it, if it's what people (I.E. me) are used to?