Earlier quoted context omitted.
It's not about you being able to do whatever you want on your machine. It's extension authors being able to. Malicious Chrome extensions are a huge problem.
Don't they have a vetting process for extensions? Even if they don't, you, the (power)user should be able to manually turn on whatever you want, should you so desire. What's stunning is that we're moving away from this, for our "security." And by then "use Firefox/something else" won't be helpful when entire websites will refuse to work on anything else but Chrome.
Putting security in scare quotes doesn’t make the actual risk go away. This is a blatant anti ad block move, but you aren’t making reasonable arguments either.