If I can run most of my current games (especially from the source engine and such) on near-to full highs, I don't think it makes sense that BL should require more than that to run shaders properly.
I have no idea why people would ever think Blockland has low requirements. The reason we harass people to keep models simple and low-poly is because of how much the game requires for everything else.
Point 1.
TF2 is probably rendering about 1000-2000 objects, most of which cannot be interacted with in any way, and no doubt that their shadows are burnt in rather than rendered every frame. Of course players are an exception to this, but how many players do you see on a server?
Blockland renders up to 200,000 objects in single servers, majority of them being interacted with and calculating shadows every frame.
Point 2.
TF2 had more than 2 people working on it.
Blockland didn't.
Hell TF2 is a pretty bad example at that, it has pretty low requirements compared to most modern games.