They just don't, that's how. The IRS has so much else going on, especially right now, that they haven't spent millions (or probably billions) needed to reprogram their miles and miles and miles and miles of computers to accept a space in a name. It seems simple enough to do, but it really isn't.
If you really don't want to make the change, you don't have to, you can print your return and mail it. But to e-file you have to conform to the computers rules.
