Nobody is saying it's a worthless approach. On the contrary-- the reason there's so much hubbub over the paper is that the approach is quite novel. Even if the end result turns out utterly wrong, much of the lead-up in getting there can be salvaged and used for entirely new directions in TCS.

In TCS, new strategies/approaches/techniques are often just as valuable as the results (and in top conferences, they are sometimes considered even more important).

We need to subject every paper to serious criticism in order to establish which morsels have merit. Hand-waving and weak logic seriously impediment our progress, so many researchers get very frustrated by it.