I think there is a very strong anti fruit, anti edible plant under current from the people that run things in the USA. Most of it is unjustified. And i hazard to guess that most of these negative feelings really spring from a negative association between growing food and poverty. Perhaps this started just after WWII. During WWII people were encouraged to plant so called victory gardens, mostly out of necessity. During affluent times almost everyone rather plant flowers or palms to show they have good taste and no need to grow their own food, ie that they are affluent enough to be able to just go out and buy their food. Ofcourse there are some wealthy people that have food gardens, but i think this is a very small minority.
It's rather difficult to break this negative association, but i think it could be done. Probably changing the laws in the long run would be much more effective than guerilla grafting. But it's good to attack this misplaced association and negative perception from different angles. So why not also guerrila grafting? There is also guerilla gardening, where people plant food plants in public spaces.
I've been wondering if one way to help break peoples' mindsets about it is to make rare fruits into "luxury" items in peoples' minds, but at the same time help them realize that such fruits are something that money can't buy. For example, I have yet to find a tasty passionfruit for sale anywhere in Northern California (when available, they're sour fruit from New Zealand), but plenty of CRFG folks grow passionfruit and we can introduce folks to the fact that if they want something tasty like passionfruit they're going to have to grow it themselves. Same for pineapple guavas, white sapote, good avocados, etc.
Yup, doing some guerrilla gardening too, though often I eventually get tacit approval of the plantings. Here are some bananas I planted in front of a 7-11 last year that have now fruited (also planted Guavas, Avocado, and Citrus) in a spot with no irrigation (I had to carry buckets to water it -- that's often the problem with guerrilla gardening here).