This is more or less me thinking out loud, but why allow upvoting for new users and not downvoting? Does it not make sense to have a barrier to entry for each?

This is more or less me thinking out loud, but why allow upvoting for new users and not downvoting? Does it not make sense to have a barrier to entry for each? Maybe the ability to upvote only happens after you've been here for 3 months and downvoting after 6 months? (I personally like tying those abilities to seniority vs. points as I tend not to comment often, but can easily identify a snarky comment that adds no value -- with no ability to downvote it).