I don't think the email made Philip feel bad. I think he saw the Quip email as an oppertunity to write a mean-ish post about Quip on his blog and advertise his consulting services in the process.

It looks like Quip links to their webpage in the first sentence of their email. So it only takes one second to figure out who they are if you care. Besides, new functionality emails are mostly aimed at active users anyway.

It's not optimal to send identical emails to every user, but everybody knows that already. There are million ways to segment your users. You can send different emails to power users and casual users. Different emails to disengaged users. Different emails to admins vs non-admins. There are always a million things to optimize and A/B test.