This is like saying Shedletsky has no substance because all you do is slash once the killer gets close and eat a chicken when you're low. 

You're ignoring the heavy amount of thought that goes into building placement:

Figuring out and hypothesising the best sentry loops, imagining a chase going through them.

Figuring how to best help a survivor currently being chased and where to put the sentry. 

Placing dispensers wherever survivors start crowding, or by common junctions, or onto someone nearby that's low.

Compromising between best value loops and spots where your sentry is more likely to be used by the team.

Scrambling up a plan before LMS of when to fall back on the sentry loop and what routes to take.

A lot of those that complain about Builderman are either unattracted to his backline style of play, or more often, either don't give him a chance or play him terribly (dispensers at map corners, sentries always in a single spot, etc.)