Should Product Hunt have a "downvote" feature?

Downvotes are a bad idea. If you don't like something, just keep going. I think the only website where downvotes make sense is StackOverflow, to prevent bad advice from spreading.

I don’t prefer any demotivation.

No no. Downvote would be a really bad idea. Every product is definitely unique on its own.

But aren't upvotes also functioning as downvotes. By comparing upvotes of two different products/ discussions. It easy to get a sense of which is liked more / is popular. In fact having a clear downvote button helps get a market sense of how many people like vs don't like. People launch product for feedback and not solace or compliments.

No down voting for products for sure. Downvoting is controversial even in discussion threads and bound to be abused.

Depends on the community I guess. A community like PH is more geared towards boosting good products (as opposed to bringing down controversial ones) so it makes sense to not have downvotes. A community like Reddit for example, on the other hand is more for expressing opinions so it makes sense to have downvotes there.

No, I feel every content is unique in it's own way but I agree to some extent that downvote kind of alerts the author about his views.