Like I said, it's just a side effect. They make money off the grift.

Prior to his current position as Secretary of Undermining Health, RFK Jr. was the head of the Children's Health Defense, whose mission is to defend children's health from various things that improve it, such as vaccines and fluoridated drinking water.

From the linked Wikipedia page:

From $13,000 in annual revenue in 2014, World Mercury Project brought in $470,000 in revenue in 2015, when Kennedy joined the organization. Its revenues increased to $1.1 million in 2018. With the group becoming a major disinformation hub during the COVID-19 pandemic, its revenue reached $6.8 million in 2020, $15 million in 2021, counting among its new donors LimeWire's founder Mark Gorton,[6][64] and $23.5 million in 2022.[31]

Basically, it's just another variation of rallying people against a problem that doesn't exist. Once you have their support, you can start asking them for money. And since your cause is a farce, you don't have to worry about getting results - just keep banging that drum and let the donations roll in. An unfortunate side effect is that you might eventually start succeeding at eliminating public health measures, but who cares as long as you're getting paid?