Death rates from non-communicable diseases like cancer, diabetes, and heart disease continue to decline but you wouldn't know that by corporate media which prints every claim that some useful product is "linked" to shorter lifespans.
Weedkillers, processed food, artificial sugar, you name it and some activist group has weaponized the public against it - and only you sending their lawyers money to sue will prevent it. The drums of the anti-science movement have only gotten louder since one of the pillars of the progressive fringe got a job in, of all places, a Republican administration.(1)
Everyone who opposes science claims they science is on their side, from Non-GMO Projekt to True Health Initiative, but it is always just yearning to make the beliefs evidence-based. Secretary Kennedy was mainstream for Natural Resources Defense Council when he was a lawyer for them.

President Obama floated him for a position in his administration overseeing EPA, but now that is works for a Republican will they speak the truth and concede that the modern world isn't killing us and that diseases are going down?

Probably not. 'The world is safe' is a terrible call to action. Anyone who looks at our Form 990 and compares it to the $3 billion in environmental groups claiming we're doomed can see how bad science is for fundraising.
Yet the data show we age better than ever, and live longer than ever, thanks to the improvements that progressives oppose. Rather than getting worse, as media suggest us due to Manwich cans and pesticides made by companies that don't fund Environmental Working Group, mortality from noncommunicable diseases like cancer have fallen in nearly 80 percent of countries in the last decade.
The good news for activists is that they know how to move the goalposts. An 80% drop in 10 years is great but they can still claim ' the rate of people not dying from cancer is going down' and some SEO expert at the New York Times will tell an editor to assign that story to a willing employee - Americans Impacted Most! - and it will get published.
That America already had fantastic improvements in health during the Bush administration and therefore naturally showed less of a decline compared to poor countries can get framed as us falling behind. That is what sells eyeballs to advertisers. And why corporate media remain so valuable to groups that hate science.
NOTE:
(1) It makes no sense that a political party which used to pride itself on being the defenders of American innovation and wanted fewer blockades now hates aspirin.
Welcome to politics.
It's obviously due to COVID-19. Though a Republican administration fast-tracked the vaccines that saved lives, Democrats successfully positioned the public to believe Republicans had caused the pandemic. Yet when it first erupted Republicans had said to cut travel and Democrats claimed they were racist. A Republican had to force the career employees in the CDC, overwhelmingly Democrats, as in all Washington, DC departments, to send out tests for COVID-19. Even then the incompetence we had been warning about a for a decade meant they sent faulty reagents. Then a Republican told FDA to issue emergency authorizations for tests to the private sector, who know what they are doing.
Today, we are told the same government incompetence and academia latching onto every epidemiological guess in 2020 means the world will collapse because if they get less government funding. The same NIH that refused to fund mRNA research (yet tries to take credit for the Nobel prize COVID earned it) now says they were about to cure it, and tuberculosis too.
The public are understandably jaded. The private sector wouldn't spend $60 million to cure tuberculous but the government body that refused to fund an Ebola or mRNA vaccine will? No one believes it. The NIH and NSF fund some things of value but they are not high-profile programs that have immediate value, they are basic research; evolutionary, not revolutionary. And such a pittance compared to private sector science spending.