It's fine to say that begging is ok. I also think it can be ok. It's even possible to call this not begging if you believe that it lacks non-reciprocity (personally I don't think so, but anyway). But it feels like you have a very weird definition of begging based on the rest of your description.
> They are not nagging
Begging and harassment are two different unrelated things that are sometimes done at the same time but not necessarily.
Not a native English speaker, so I may be far off on this discussion, but for me this kind of activity where you write a blog post and ask for donations is closer to busking than to begging.
> They are not nagging
Begging and harassment are two different unrelated things that are sometimes done at the same time but not necessarily.
See the difference between
https://en.wikipedia.org/wiki/Begging
and
https://en.wikipedia.org/wiki/Aggressive_panhandling
> you do not have to buy them a coffee/pizza/metaphorical food item.
Yeah, that's how begging works. You do not have to give money to the person begging.
> You can go on with your day.
Yes, that's how begging works. If they had you at gunpoint it would be called robbing.