The story is not who signed the Barrington Declaration but that its ideas are unsupported by scientific evidence. Deliberately and purposefully employing SARS-CoV-2 as your vector to achieve herd immunity presents many dangers and unintended consequences.

Medical Mythbusting Commentary for October 15, 2020

Source:
Herd immunity letter signed by fake experts including ‘Dr Johnny Bananas’

Reference:
Scientific consensus on the COVID-19 pandemic: we need to act now

And for those who propose that Sweden has the right approach:

The Swedish COVID-19 Response Is a Disaster. It Shouldn’t Be a Model for the Rest of the World