Isn't it sad that a company that totally dominates modern email, plays so fast and loose with email standards?

And not just obscure standards; email addresses are very much public-facing elements of email. The expectation when you register an email address is that that address is now uniquely associated with you. The public does not expect that an email might be delivered to other inboxes than their own.

Why does gmail elide dots again? There must be some reason why a big email provider would deviate so egregiously from the conventions all other email services comply with.

/me not a gmail user, except for certain account recovery purposes.