Even those that are still B2B eventually need cash flows from consumer businesses. Hence the statement that we won't fully realize the losses until Q3. Less spending by consumers depresses all businesses, some sooner than others, but FANGs are definitely hurting.
The cool thing about B2B, as opposed to consumer offerings, is that the contracts on those are usually multi-year. Just because the client enterprise suddenly receives less revenue from customers, it doesn't mean that they would be able to stop paying MSFT until the contract term is over. Unless this current lockdown situation lasts multiple years, it shouldn't affect things significantly.
AirBnB is now paying for 7000 less exchange accounts and office licenses, and you have yet to explain how FANGs are doing well.
You are assuming the scenario where consumer division was making a lot of money. For a lot of very successful B2B businesses, their consumer division exists mostly to make small gains, while acting primarily as a getaway or advertisement for their B2B offerings.
You would be surprised to find out how much more revenue (and profits) a company like Microsoft makes on their B2B offerings compared to the consumer ones.