May I ask how they approached you about this? (looked into your first posts and didn't see any signs of it)

Generally newcomers are very much not in any risk of downvotes unless there's something suspicious about their activities. The way rewards work here and the immutability of them after posts pay out opens up ways for abusers to try and trick the community into being other people, having put effort into the content, etc, when in reality they're the same person that created many other accounts trying to copy-paste text on that belongs to others and so on. Those are mainly the only accounts that receive downvotes. If for some reason some whales/larger stakeholders are having a bad day and purposely attack new accounts with downvotes it usually gains attention pretty fast and others can step in to counter such behavior. They may be whales and they may retaliate on those countering their downvotes but there's also whales that value the new users' starting experience beyond the consequences or are mostly passive and can't be retaliated on in terms of post rewards, etc.

Downvote mana is also only 25% of upvote mana, whales going bad eventually means they'll have to use their upvote mana to downvote and continue said activity which will start eating at their curation rewards and growth, at lower prices like now it may not mean much to them but it might eventually. Others countering their downvotes with upvotes may also earn less returns due to the downvotes but they can band together and take the loss of APR hit together so it doesn't hurt as much.