Reddit karma is +1/-1. Why should SE rep be +10/-2?
In short, the voting and reputation structure are optimized for a Q/A site rather than a system that ranks popular opinions.
There is asymmetry in the meaning of upvotes and downvotes. The value of a Q/A site is how many people find a post useful, so upvotes should be a fundamental metric for the value of a question, and downvotes merely a tool to incentivize high quality. From our help center:
Voting up a question or answer signals to the rest of the community that a post is interesting, well-researched, and useful, while voting down a post signals the opposite: that the post contains wrong information, is poorly researched, or fails to communicate information.
Upvoting and downvoting would be symmetrical if we only downvoted posts that were actively anti-useful i.e. wrong and misleading. But we downvote more than that, because questions and answers are often unclear or poorly constructed.
Due to the higher effort put into each post, being downvoted here hurts significantly more (at least to me!) than it does on other sites. So as not to discourage users from posting, so we ease the pain by reducing the reputation impact of downvotes.
- Reputation is tied to privileges, and it's wrong to exclude users who have controversial questions from the full experience of the site (commenting, seeing vote counts, etc.).
CG.SE is not exactly a Q/A site like the rest of SE, but these points still apply.
Finally, please don't deliberately post poor questions to attract downvotes to test something. We're friendly and have a chat to ask about such things.