Why do I lose 1 reputation for downvoting answer? This discourages a lot of people to downvote answers that really should be downvoted.
This has been discussed many times, both for questions and answers. Jeff Atwood put it most succinctly back in 2011
This is done to make sure downvotes are cast only when you feel strongly that something is incorrect / wrong / dangerous / of low quality.
And the stats over the last decade show that it doesn't discourage a lot of people at all. 1 rep is really nothing
Worth reading the when should I vote FAQ and Reputation FAQ for additional info, and in fact the whole FAQ on meta is invaluable.
1$\begingroup$ Adds up. I might not downvote a 6th post after downvoting 5 because I don't wanna lose more rep @Rory Alsop $\endgroup$ May 23, 2022 at 17:18
2$\begingroup$ Just checking on my main site - I have upvoted 14000 times, and downvoted 4700 times. It really makes no difference at all. Remember, rep is pretty much irrelevant. It happens to encourage good behaviours, but behaviours should not be deliberately made to gain rep. $\endgroup$– Rory Alsop ModMay 23, 2022 at 19:06
$\begingroup$ @RoryAlsop Reputation is indeed quite irrelevant... if one happens to be a moderator. Otherwise, it is quite relevant for the less reputable users, like myself, because of certain functionalities being accessible only after passing their relevant thresholds. What is more, having voted down 4700 times does not necessarily mean -4700 reputation, because the posts you had downvoted give you that 1 point back once they are deleted. Meanwhile, the profile's downvote counter stays the same regardless. $\endgroup$ May 23, 2022 at 21:00
$\begingroup$ @RoryAlsop I highly suspect this to be an intended mechanism, since it somewhat "rewards" accurate downvoting: that is, downvoting those posts which happen to be deleted later. $\endgroup$ May 23, 2022 at 21:02
I remember having read somewhere that this mechanism also has the purpose of discouraging people from downvoting other "competing" answers one the questions that they also have submitted an answer. It makes sense, but is definitely not the only reason; the 1 point loss is also applied in cases where one did not submit their own answer in a relevant thread.
Interesting thing is, voting down answers that are community wikis does not result in 1 point loss being applied to the voter. This fact gives an useful hint as to what the reason for this mechanism's existence is. Posts that are community wikis do not affect the owner's reputation score -- in other words voting such posts down does not result in the owner losing 2 points. Having considered that, it is quite obvious that the mechanism was placed there to balance the voting dynamics. The reputation loss is a penalty for having made someone else lose reputation. Voting down, unlike voting up, is not seen as a cooperative interaction and therefore it is discouraged in order to facilitate the development of a more cooperative environment in the network.
It reminds me of a tale of a man who hated his neighbour. One day, the God had spoken to the man and gave him an offer: the man could ask for anything he wants: any amount of money, goods, etc. but the caveat being that no matter what he asks for, his neighbour will get twice as much. In response, the man took a while to think about this, then happily asked God to gouge one of his eyes out. I cannot help to be reminded of this tale and smirk anytime I think about those -2/-1 reputation penalties in the context of answer downvotes. Just my two cents.
Not directly related but nonetheless tangential to this subject is the article about coordination games.
3$\begingroup$ Remember that community wiki has been deprecated and should not be used except for specific reasons such as creating FAQ posts $\endgroup$– Rory Alsop ModMay 23, 2022 at 19:04
$\begingroup$ @RoryAlsop Hey thank you really much for heads up. I was not planning on using community wikis for my posts, I was just using them as a hypothetical example in my philosophical thought experiment aimed to deduce the intended reason for reputation loss related with downvoting. Nonetheless, I appreciate the information a lot. Cheers. $\endgroup$ May 23, 2022 at 20:04