I wouldn't be surprised if that integration is outright illegal in EU due to GDPR, thus putting HIBP in trouble for ingesting PII without any legal legitimacy.
And the first reply being "It is not an invasion of privacy" just shows incompetence on privacy topics. It is never a valid answer.
Which is really concerning, for the lead developer of a home automation system that "fights for the fundamental principle of privacy" as per their mission statement.