If the thing suggests the EMAIL (+ associated password) has been compromised for some unknown account then to do a risk assessment I would have find which account it belongs to, not which currently-in-use passwords match the same datasets.
Those are different queries, providing different bits of information.
You don't need to query old passwords, only current passwords. If you're talking about accounts that you've forgotten the password to: then do you care about those accounts? If yes, probably best to do a password reset and set a new password. If you don't care about the account, then why bother?
As for why HIBP doesn't provide an API linking passwords to emails: HIBP has no database that links passwords and emails. So they can't provide any way to query that. They don't want to be in the business of linking passwords to emails.
How's this for making it actionable:
Regardless of whether or not someone can associate it with your email, if your password has been seen in the wild, change it.
There you go.
password: 46,628,605
your password: 609
good password: 22
long password: 2
secure password: 317
safe password: 29
bad password: 86
this password sucks: 1
i hate this website: 16
username: 83,569
my username: 4
your username: 1
let me login: 0
admin: 41,072,830
abcdef: 873,564
abcdef1: 147,103
abcdef!: 4,109
abcdef1!: 1,401
123456: 179,863,340
hunter2: 50,474
correct horse battery staple: 384
Correct Horse Battery Staple: 19
to be or not to be: 709
all your base are belong to us: 1
Edit:
louvre: 7,219
Only 1, really?
Without spaces, it's 681.