Yeah, ITAR restricts export of guided rocketry systems, which this qualifies as. He’s mentioned ITAR in some of his videos as one of the reasons he doesn’t distribute his firmware or schematics.

The Trump Administration seems to have significantly loosened ITAR for almost everyone (IIRC primarily intended to make it less onerous for small arms researchers and manufacturers), including individuals, and specifically addresses removing some forms of software and designs from the USML. If it's firmware or designs as far as I'm aware there may be no problem with that now, even if it's rocketry or guidance software.

Among my many random roles in my job, I do export technical licensing review. I can assure you the industry practices on ITAR have only tightened in recent years, and the only language clarifications that have affected my review policies are over 4 years old.

Small arms researchers and manufacturers who are inside the US should not be affected by ITAR nearly at all. The only restriction ITAR / EAR places on a US company is to not sell or share technical assistance (any kind of design, etc) with any foreign persons (which includes public disclosure).

What he may have done is change the classification of certain small arms technologies. But that does not affect the "ITAR" process or its "looseness".