You're falling for a marketing trick.
What that type of section usually means is "there's someone from Microsoft that signed up for our service using his work account", sometimes it means "there's some tiny team within Microsoft that uses our product", but it very rarely (if ever) means "the entire company is completely reliant on our product".
Yes and no. Generally logo usage requires permission. While the usage isn’t the whole company, it’s enough to justify some sort of logo usage.