The rate of earning merit as a newbie is really difficult that I think even on average making 20 posts doesn't guarantee merit and such a user might not be a spammer rather trying to contribute, learn and others which include what you added on your post about those coming to make complaints.
Nope, the lower the rank, the easier to get merit.
I will still stand on this ground that earning merit as a newbie is really difficult. Reputation plays a role here and while is not like it's not the main criteria it helps others to be sure this is not just another newbie using Ai or something else in order to rank up.
I don't know hie you distribute your merit but I will say people are more mindful in sending merit to a newbie than a reputable account.
I think many users give merit based on the users' rank and knowledge, if they're not that good, but they're still newbie, they can still get couple merits. But if they were Hero or Legendary, but they post like a newbie's knowledge, people won't merit them.
I think this occur when the newbie is showing a sign of willingness to learn and not too far off from the answer. While reputable accounts here might not earn from it but still can depending on how they portray themselves in such situation, someone is willing to learn and doesn't Speaks with pride when they lacks knowledge in that regard will likely earn merit and be enlightened.
The later by the way is more important.