Not to mention everyone who uses email may now need to have a Google-account to read email, even if they don't use Google mail services themselves.
I wonder if they had any discussions about this internally, and if anyone on the engineering team objected to such changes. I find it hard to believe such a change was done by pure accident without anyone noticing.
They're pushing GSuite for governments, corporations, schools... Things like 'read receipts', email recalls, and such are common questions and common scenarios that are supported by their competition. I bet this is in a well curated list of requests from schools, healthcare organisations, and MegaCorps alike...
For people outside the Google sphere there are numerous alternatives to make this appealing. A single-use link, for example, or just slapping OAuth on there. The baseline is open email, so any kind of trace-ability is a huge improvement.
I wonder if they had any discussions about this internally, and if anyone on the engineering team objected to such changes. I find it hard to believe such a change was done by pure accident without anyone noticing.