According to Stack Exchange Employee animuson ♦,
We've established in past discussions that abuse of the system qualifies under the offensive flag. Posting gibberish that doesn't mean anything is definitely abusing the system.
We do have to be careful in situations where it's not as clear what the intent of the user is. Someone mashing their keyboard to get a bunch of random letters into a box is clearly abusing our system and they should be flagged and blocked. Someone who looks like they may have just ended up in the wrong place and have no idea what they're doing... well, flagging them as an abusive user and blocking them outright might be a bit much. If you're absolutely sure they're intentionally trying to be abusive, by all means. Otherwise, you may want to just stick with not an answer. 1
My educated guess is that the following example is definitely abusing the system:
hi i am piper kimbrel i have a best friend named ella
It's also okay to flag them as Not An Answer, or Very Low Quality. But doing so will send the post to the review queues, and will require at least 6 other reviewers to recommend it for deletion. Why waste their time? Flagging it as "rude or abusive" by at least a few users will remove the post automatically (and penalize the poster).
Please note that the example given above is not spam, and it should not be flagged as "spam".
If the post was actually useful, but then if it had some additional irrelevant text or gibberish, instead of flags, please just edit out the useless parts from the post.
Also, do provide guidance to newcomers, as that will greatly reduce any further low quality posts from them.
Your second example is simply Not An Answer. It is not gibberish in my view.
Before we can eat prime rib it has to go through a process.