you're right according to official reddiquette. the intended use of the downvote button is to de-emphasize irrelevant content and content that otherwise doesn't contribute to the conversation

i have seen it argued that its intended use use doesn't matter versus how the majority of people actively use it, similar to language and symbols. usage evolves with time, so meaning evolves with it. personally i prefer the intended usage but i can see where ppl who make this argument are coming from.

the lemmy instance i joined doesn't have a downvote button at all!

edit: here's the official reddiquette archived on the wayback machine

In regard to voting:

Think before you downvote and take a moment to ensure you're downvoting someone because they are not contributing to the community dialogue or discussion. If you simply take a moment to stop, think and examine your reasons for downvoting, rather than doing so out of an emotional reaction, you will ensure that your downvotes are given for good reasons.