You seem to have a VERY narrow definition of commercial use which involves selling software or being a software service provider. There are a vast majority of companies manufacturing/distributing/retailing and providing services for whom the GPL imposes no restriction at all. The MS release seems to prevent all commercial use not just commercial redistribution/binary release making it a FAR broader restriction than the GPL.

For MS and a surprisingly small (in terms of total global economy) number of other businesses selling closed source software (or software dependent on other non-Free software components) the GPL imposes very real restrictions.

I would argue that they are in no way arbitrary but have a clear purpose and objective to further increase the amount of Free software in the world. You may or may not support or want to assist this objective but it certainly doesn't feel arbitrary to me (I've taken the 'capricious; unreasonable; unsupported' definition of arbitrary from Dictionary.com as my interpretation of your meaning).

Edit/reply:

Can't reply to you for some reason. No citation but you have missed my point. I wasn't comparing Open Source Industry to closed source software industry but really the software industry to ALL Other industries (and individuals) in the world. Basically software consumers rather than producers (of which closed source companies like MS form a large part).