It's not like swinging your weapon twice to kill a zombie is a huge time investment. Demon eyes have a hard time hitting you if you keep moving, and fairly easy to jump over them, zombies aren't too hard to leap over either. In caves it's a bit more of a problem.
No argument here. I don't mind traveling and fighting and interruptions the way it is in Terrarria (though more danger would be nice). Its the whole "oh we should make it so one out of a thousand zombies will drop the key you need to open the chest you just found" proposal that kicked this off, not having to fight enemies as we travel.
I don't think it's fair to call fighting battles from A to B "grinding". Otherwise all games with random encounters is considered grinding.
Being forced to fight those battles because the variety of other options given to you means you won't be strong enough to finish the level IS, though. That's the difference between a game like Fallout (where running away from every random encounter is a viable strategy that will not noticeably weaken your character) and Final Fantasy (where you often have to take laps around a dungeon a couple times to accumulate enough experience to have a chance at defeating the boss. Well, I did anyways, most because I put off grinding whenever possible).
In Fallout, the random battles are not frequent and not vital to the characters progression. They were also, often, dangerous challenges. And when they stopped being so, you were rewarded with the option of skills and abilities that would let you avoid them completely. It is very possible to have random battles that are not grindy in the slightest, it's been done. Final Fantasy games have grind as a central component of their reward mechanism, however, so their random battles are notably grindy. Game-forced grinding is still grinding, and all the Final Fantasy games (and many JRPGs in general) had plenty of "You MUST kill 200 enemies before here and the end of the area to defeat the boss, unless you've spent extra time grinding somewhere else". As I said, it wasn't terrible, but you can't say they had a policy of "no grind". It's absurd. At best, they simply didn't care.