Not just someone complaining about how the new account they just made for reddit is limited. Especially when it's something that's been around for like a decade.
You are in a "bitch about reddit" community complaining about people bitching about reddit. Bruh, this is why this place was created, to bitch about reddit.
Your second point is valid, also this feature is to prevent spam from newly created accounts so why is this worthy to even complain about? New accounts shouldn't be trusted as much as well established accounts, and it's generally not that difficult to get enough karma just by commenting. For humans it does not pose that big of a barrier to entry, for bots it poses some.
Whenever a spammer or spam bot is identified through reporting and gets banned, the spammer just makes a new account and continues. As a result spam accounts tend to be “young” accounts with low karma.
But limiting the posting and commenting powers of all young accounts and accounts with low karma, they limit how quickly someone can spam Reddit. There’s also less obvious limits to like limiting activities from the same ip addresses. (To prevent working around the limits by simply creating 100s of accounts at a time)