If that is true, it makes perfect sense. And I am 100% backing cPanel's attitude.
I have several customers that rely on cPanel's email, and despite all the email configurations are 100% correct (SPF, DKIM, DMARC, the domains are not blacklisted, they are not sending newsletters, etc), despite all that, all their emails always end up on these providers Spam folders no matter what.
A colleague o mine that works in another company told me last week that he lost a customer just because he couldn't prevent their emails going to Spam.
I would say that this is NOT only a Microsoft's problem, but also Google...