No need to get upset over it, dismiss the banner and move on.
When Wikipedia asks you for donations every year do you get all pissy and call the staff volunteering their time with various stances and opinions useless folk that don't bring new features to it? When a food bank you donated to sends a thank you and asks if you can donate more, do you suggest their work is worthless?
Go ahead and use, support and recommend Piefed if it's better for you, sure. Block nutomic, dessalines or all of lemmy.ml if you don't like their opinions or moderation policy, absolutely. But IMO, throwing shade and disrespect towards the people that built the software that Piefed was born out of is uncalled for. The way Lemmy and the Fediverse is set up, you can use the infrastructure without any real association with its founders.