I 'm going to give you a brief explanation of why all of them sound so similar, ...i originally wasn't planning on going this technical about it but given the circumstances, i will.
You can arguably say they do not sound the same but ultimately all their sounds have derived from the same fundamental pieces of software.
Which is exactly what I said about saying all metal sounds the same because they all use guitars. Still, compare Behemoth with Dimmu Borgir or Children of Bodom and youll see they sound nothing like each other. And if you cant hear the difference, I suppose youre just tone deaf then :P
So, they all use the same sort of software. What do you expect? Want them to first write their own software from scratch?
And yes, they have a lot of things in common. Thats why they all fall under the category Aggrotech.
But yeah, thats a personal choice you make. Either like 1-2 groups from each genre and dub everyone else imitators for using the same software or look beyond that and like a lot more. Thats just your taste and its quite pointless to discuss taste.
Give any two painters the same tools, lets say Vincent van Gogh, and Henri Rousseau...
Both have the same brushes and paints, but use vivid colors and emotional impact, from which you could classify them as post-impressionists, but just because they're both considered modern artists, doesn't mean their work is anything similar or alike. Same could be said about those Metal bands you mentioned, they all have a lead singer, a guitar, a bass, and drums, but is their own applied skill and talent what makes them unique under a similar genre.
Same goes for this Aggrotech bands, which due to certain basic similarities & tool-sets, one classifies them as "Industrial", unfortunately due to their lack of creativity & originality, they bring nothing innovative to their sub-genre.
But anyways, im dropping this as it appears the last resource for ignorance, has turned into personal attacks.