He's asking you to donate money to him, and in exchange, he will give you access to the presets he's working on. It doesn't sound much different, but in the eyes of the law it's very much not the same thing.
In most countries that does count as a transaction, rather than a donation (since you are getting something material in return for paying). So it is the same really. You'll notice Patreon purposefully does not use the term donation anywhere.
Do I approve? Not really. The time and work spent by all the shader authors to write their shaders and by myself to make ReShade is considerably higher than the effort needed to create a preset, so I don't consider it particularly fair to build upon all that work from others and still take money without giving back. But yeah, it's still perfectively legal (ReShade is permissively licensed after all and does not restrict usage in any way).