Corruption is the nice blanket term. But the way that word is used 99% of the time will make that not ideal. Corrupting is also an option.
Vitiation doesn't really work but it sort of does. Most people probably wont know what it means off hand, though.
Subvert isn't ideal either.
In this instance what coercion would be directly saying is that the manner in which the opinions would be changed would be untraditional and not ideal for the victim (which arguably is the case here). It should be noted that typically one is being coerced to do something negative too, and thats why i think its somewhat appropriate for this situation.
I'm going to assume that the main thing thats negative is the changes themselves, not the manner in which the changes are made.
There are many words which refer to negative ways inwhich persuasion can occur. But not many touch on whether or not the changes themselves are good or bad. Seduce sort of works, but not in this setting. I think corrupt may be the best one.
Theres beguile, to influence by trickery, flattery.
Cajole, to persuade by flattery or promises.
Coax, to attempt to influence by gentle persuasion, flattery.
Wheedle, to endeavor to influence (a person) by smooth, flattering, or beguiling words or acts.
I think "influence" may also be a contender. Influence generally refers to (and maybe implies?) negative effects. And i don't think theres much in regards to connotations on the manner in which the influencing occurs.
Brainwash, again, implies that the process is negative too.
Proselytize means to try to get someone over to your side or your way of seeing things. But it implies intent and i think you want to allow for the possibility that the influencing is unintentional (which would definitely be the more professional way of phrasing it).