yes, discouraging unencrypted SMTP on port 25
My former ISP has it blocked outbound everywhere except their virus scanning SMTP relay -- a measure they put in 20 years ago in response to the early e-mail worms of the early '00s
Nowadays in order to combat spam and spoofing, an "unofficial standard" is emerging that everyone use SMTP over TLS on a different port and have to use verification mechanisms like DKIM
I'm not surprised to see cloud providers enforcing it too