I think you're trying to apply that meta question/answer to this question when it doesn't actually relate in this case.
In my answer to "To what extent do we respect the OP's request?", I'm talking about people who have made a decision that affects themselves and we need users to avoid telling them that their decision is wrong when it does not relate to the question at hand.
If I've decided to be an omnivore, answers should not say "You're wrong to eat animal products" - and the inverse is true as well.
If I've decided to be (insert religious belief/non-belief), answers should not tell me "You're wrong to believe that, my religion/non-religion is the only correct one".
Deciding to be a specific religion or eat a specific diet or support a specific party or any other non-IPS decision - what you decide is generally going to be irrelevant to your question, so answers that argue with that decision are non-answers. We're only here to discuss Interpersonal Skills.
In this situation, I think that this would only be in conflict if someone answered the question saying:
Just give him a high five, he's only being friendly.
Regardless of why she's afraid of this man, she has decided that she does not wish to interact with him and that is her choice, we should respect it. As far as I can tell, while the answers may tell the OP that her fears are misplaced, none of them tell her to give him high fives. Every one seems to give guidance that comes down to "if you don't want to do it, don't do it".
And if you don't feel comfortable don't give high-fives and don't stop to talk to him (and no eye contact). Just say you are in a hurry, avoid passing by him and/or if he follows you around or bothers you, speak with an officer.
If you're not interested in engaging with this person you could just keep walking, I'm sure many, if not most, people do.
Mari-Lou A's answer:
If you wish to be ignored, because you feel safer that way, then as you approach his patch, take out your smartphone and pretend you are conversing with this imaginary caller. You don't have to speak, you can simply nod and say “uh, huh” but make sure the vendor sees that you are busy.
Repeat this noninvasive action two or three times, and the vendor will (or should) understand your body language. If despite this he still approaches you, ignore him, look down on the sidewalk and continue walking. There is no need to exchange words if that makes you feel too uncomfortable.
No one is telling the OP to give him high fives.
In this case, I see the answers that either solely or in part mention that the OP's interpretation of their interpersonal interaction with someone else may be skewed is within the scope of this site. Much like our questions where the answer is "don't do that", we are doing due diligence in our answers to address what many people think is an overreaction.
That being said, I think that it is important to note what Shog wrote in his answer to another meta question:
First off, let's get one thing out of the way: no one asking questions here is objective.
I don't mean that in some vague "true objectivity is impossible" sense; rather, as a practical concern we have to assume that if you're coming here for advice then you're stuck on finding an effective way to communicate in some situation - that's your perspective, that's what drives your question, and the job of folks answering is to help you improve your understanding in such a way that you're able to resolve the problem.
The most important part of this as it relates to this question is the last clause:
the job of folks answering is to help you improve your understanding in such a way that you're able to resolve the problem.
Telling someone the answer they want to hear is not what we're here for. I think that the answers to this question - What to do with questions about "getting around" peoples' boundaries / autonomy - apply here, too. If someone has a skewed interpretation of the people they interact with on a regular basis, particularly when based on interactions with people other than the person they're asking about, I think it's fair to let them know that they may not be reacting to the situation appropriately. Whether others agree will be borne out in the votes.
That said, we are not here to diagnose people. While telling someone that they may benefit from communicating with a therapist may be part of a complete answer to a question like this, the answer should definitely also address the interpersonal interaction at hand.
Here is a solution to your immediate problem with this street vendor ____. This should address it but it seems like your concerns about being attacked (based on the information you have chosen to share with us) are misplaced and it might help you to talk about it with a professional.
I think that "part of helping someone improve their understanding" is pointing out that your fears may be negatively affecting your interactions with others.