It also requires:

1) the ability to avoid debris at those speeds (which would obliterate the ship) 2) to survive radiation, 3) the nearest stars to be of value life-support wise, 4) a couple of generations to pass, 5) us not to hear back from the mission for years upon arrival,

So, a more far-fetched version of solar system exploration, with the next steps even further...

Did you expect it to be easier than solar system exploration or what? The engineering problems have plausible solutions: You'd need a lot of water anyway so a shield of ice can handle debris, the ice, together with the ship's own mass, also shields radiation quite a bit.

This is pretty different from a "fairy tale" and not addressed at all by the blog posts you used as arguments.

Unless you are moving at near light-speed, where a proton is already a problem, debris do mostly not exist in space. If you want to reach one, you'll have to target, and even then it's hard.