I think one of the thing that irritated some people is that this time they are not paying for more, they are paying to remove a nuisance (tracking). This is something almost only seen in proprietary apps.
I’ve paid for a bunch of Foss and non-foss applications through the years but never for the “remove ads” model. JuiceSSH is one such example. The base app was so useful that I knew I had to get the additional functionalities and paid a fair amount for them.