"The applicable tech is already under a patent license (see OATH and IETF documentation)."
There's patents that cover a specific tech, for its uses, for underlying mechanisms, and for vague extensions. These are the risky types that show up the most with most of it obvious to point it shouldn't be patented. Expensive to fight, though. Microsoft goes for all three. So, either IETF would have to own patents for all use cases and underlying techs or Microsoft would have to issue patent license for all such categories if they have any. A patent license for the whole product to be used or cloned however, as in the open licenses, is still safer.
"There's no greater risk with a Microsoft option than a Google option"
Unbelievable. You've looked at the court histories to find that Microsoft and Google have caused about equal damage to companies with patent suits, lock-in, or obsoleting core products. They haven't. Google doesn't even compare, esp the billions Microsoft extracted with legal suits, except on encouraging lockin where Google at least stays ahead of most competition in terms of capabilities instead of stagnating. Virtually no comparison in actual damage done although I'll concede Google is becoming more like Microsoft every day in terms of sneakiness & lock-in strategies.
" I realize a lot of technical folks are still highly suspicious of Microsoft"
You should try the non-technical folks who've been burned by them with Windows activation failures, forced upgrades of hardware, forced ads on their paid Xbox Live, BSA developing snitches in organization, licensing schemes, lawsuits over nonsense patents, and so on. You don't have to be technical to be suspicious of an organization that pulls as much BS as Microsoft. I've met many non-technical people using Mac's (or enterprise Linux) because they didn't want the trouble of dealing with Windows or Microsoft. Worst horror stories I hear from Apple users in terms of company are the "Apple tax" and issues with non-Apple hardware. Also the PPC to Intel transition at one point. Collectively not in same ballpark as Microsoft's behavior, esp in financial risk.
"Microsoft's option has the best cross-platform reach and is the easiest to find in the respective app stores."
This could be true. Again, if it's usable, better than others, and you can avoid lock-in, then sure go for it as it's best option. Also, go for it if others are so bad they wouldn't use them anyway. Better than nothing. These are potential use-cases.
"You probably should be using at least one by now, if not several. "
It usually means they hit two targets instead of one. My opponents can do that. I just don't trust the accounts at all. I assume my machine is compromised then work from there. Far as riff raff, I use a Linux desktop, update my software, secure the wireless, make randomish passwords, and so on. I could improve it but the few times I've had to change something was when online service itself was compromised. Yahoo and LinkedIn being only ones I know recently. I'm not saying other people shouldn't do it necessarily but little benefit for me given threat profile.