And the number of markets Microsoft completes in now is tiny. This isn't the 90s where Microsoft competed in slews of consumer and business markets. The potential upside from the Cloud team slurping up secrets from competitors in literally ANY other business segment, is dwarfed by the losses that would hit MS.
Now of course that doesn't mean some corrupt fool in sales won't risk destroying the company so he can make his yearly bonus (that very thing has brought down companies before!), but Microsoft internally has a lot of motivations to ensure that doesn't happen.
So, don't trust Microsoft saying "trust us". Trust Microsoft being greedy and wanting to keep growing the cash cow that is Azure Cloud.