Plumbing doesn't harm the people in the desert. Plumbing isn't an inherent bad.

The system of imperialism that enables some to starve while others eat is inherently bad and is propped up and legitimized when you act within its framework.

Adding plumbing to your house isn't saying "it's normal that people are dying of thirst." Structuring your impact around donations is, meanwhile, saying "though this system results in people starving while others throw away half their food, we can only solve these problems by working really hard within the rules this system defines, and then lending aid within the rules this system defines." After all, there's only one way to make money enough to be "impactful..."

This is a slightly tangential example, I don't want to be mistaken that I'm saying they're equivalent: Buying and freeing slaves is not a good form of activism when trying to overthrow slavery. It's doing the exact opposite: upholding the institution of slavery with every purchase. Legitimizing it and even in fact funding it. You tell yourself you're at least slightly reducing harm but in reality you're motivating slave catchers to go find more people to slave - and meanwhile btw you're doing nothing to address the fact that slave catchers in your own country are just grabbing the slaves you freed.

The only truly ethical choice for activism against slavery is to break chains and use violence against anyone that prevents you from breaking chains.

Again, not exactly equivalent, just an example of how "helping" can actually prop up the thing you think you're trying to take down.