Maybe that’s a reason to not feel bad if it violates the TOS but there are real consequences to doing so so perhaps your response isn’t that helpful.
What consequences ? Breaking ToS can get your account suspended if you even need an account for doing this, not sure what else breaking the TOS really implies.
I don't know if Google can claim ownership of this data as it's customer generated and publically available.
Not exactly - robots.txt will prevent Google from crawling the page but it might still show up in search results (without a snippet or your page title) based on how others link to it.