Why argue only about the transmission? Why not have cars with manual ignition?

Because on an enjoyment:effort scale a manual transmission ranks a lot higher than stuff like hand starting, manual ignition timing or manual chokes.

If you dislike machines making your life easier, stop driving all together.

Do you also tell photographers to quit photography if they use manual mode to control their camera, or woodworkers to only use powered tools instead of hand tools? Sometimes having that bit more of a connection to or control over what you're doing is just more engaging or more enjoyable - maybe you don't care about that when driving but there's a lot of people who do.