I disagree that it's completely different situations. I have not seen anywhere in the legal structure that allows such moves if advertisements are enabled. It is still a company abusing their monopoly situation to influence another market.

In fact Google did it worse by blocking browsers purely by user-agent to key google services like maps to block the entry or Fire devices or windows phone devices.

Both cases aren't acceptible and both should be punished imho.

It is not, because they are not a monopoly.

Google Search is more of a monopoly than Microsoft Windows is last I checked.

Totally agree.