For existing sites, switching from HTTP to HTTPS is in effect, starting over. All the ranking factors and metrics have to be rebuilt from scratch including links, trust metrics, etc. This is why all the negative hype.
Switching from HTTP to HTTPS is disruptive and why people complain. It did not occur to them that there would be an additional cost to switching from HTTP to HTTPS. Conceptually, anytime there can be different content served, it is a new site. However, going beyond that, each domain name, no matter how it appears, for example, www.example.com versus example.com are stored in the index as separate sites. This includes HTTP versus HTTPS. There is a good reason for this despite the tradition where these sites wold normally be the same. Each of these sites within the index has to build trust and domain metrics all on their own. The largest factors would be trust and links.
If you do not have a HTTP site and start with HTTPS, then there is no downside. You are not starting over but rather building metrics for a single site. For the record, Google may be a 900 pound gorilla, however, it does not make the rules. Each time it tries, it gets shutdown. Yes. Google wants the world to be HTTPS, however, it is fully your right to use HTTP and they will just have to deal with it. HTTP does make sense most of the time.
Here is some of the backlash:
Here is where HTTPS helps.
Other than the obvious security argument which is a powerful one for both the user and web site owner, HTTPS is a trust metric that positively effects a sites Trust score. Today, there are many factors that can outweigh the effect of HTTPS, however, Google is making noises that HTTPS will have more than a the slight score increase it is today. And that makes sense.
Considering the quality of the certificate, some companies do vet who they are giving certificates to, the value of the certificate can ensure to any search engine that the site ownership is actually verifiable. Google does use registration details in evaluating site trust, however, having an additional layer of vetting helps with trusting a site.
As far as earnings with Adsense HTTP versus HTTPS, there is no difference. Any complaint is a result of the disruption in switching from HTTP to HTTPS.