There have been allegations in the UK of voter intimidation after postal ballots became easy to obtain: people would require dependents to hand over their ballots, fill them all in, and post them back. Now, it may be that this didn't happen or wasn't statistically significant, but if people are not required to turn up and vote in such a way that they can't prove to someone else how they voted then there's the potential for doing this on a large scale.
Of course one solution would be to allow individuals to vote repeatedly but only count their last vote, though if you capture someone else's voting credentials then it's very easy to vote en mass with everyone's details at one second to the closing deadline...
None of their competitors even OFFER the option to have an "F-Droid" or to remove their respective equivalents of play services
I'm not sure what your point is. 'Other people are worse' is not a defence in an antitrust investigation, unless those others have enough of a market impact that you're probably not going to be in the antitrust regulator's jurisdiction anyway.
Google is using the fact that they effectively have a monopoly on application distribution (yes, I know about F-Droid and the Amazon store. Most apps I want come from F-Droid, but I'm hardly a typical user and the rest come from Play because they're not in the Amazon store) to gain market share in other areas.
Paying for someone else's bills is always welcome in my book
In antitrust circles, this is called 'dumping' and can have very bad effects on the health of the market.
Let's take a web browser as an example. Chromium has a number of sandboxing strategies that provide different levels of protection. On Linux it can use chroot (which can't restrict network access), SELinux or seccomp-bpf (which aren't great because they don't differentiate between different instances of the same program, so one sandbox can access anything that any sandbox can access). On OS X, it uses the TrustedBSD-based sandboxing framework. On Windows it uses kernel ACLs. On FreeBSD, it can use Capsicum, which provides the best isolation (though this support isn't fully upstreamed, it's in progress because Google is porting Capsicum to Linux for the ChromeBook). On OpenBSD, it can only use chroot, because the OpenBSD developers believe that complexity is the enemy of security and don't implement security features for userspace software to use (they did have systrace, but it was shown to be trivially vulnerable to timing attacks and never fixed).
Bottom line: the features that a kernel provides can have a big impact on overall system security, and OpenBSD lacks a lot of the security features that you'd expect from a modern system.
Campaign contributions, on the other hand, are not speech.
The problem is that this distinction is abused. You may not be allowed to donate to a person's campaign, but you can pay large amounts to have ads run on a particular issue that just so happens to be one of the core parts of a particular candidate's campaign platform.
An authority is a person who can tell you more about something than you really care to know.