If that's true then: Sixgill = "the new evil"!

But I highly doubt any of those things Sixgill claims it is capable are true! To accomplish even remotely such things, one would need huuuge resources, resources just governements like the USA, UK ect could provide (Billions of Dollars) but not an isreali "start up". And even with those resources you just can't (at least not at this moment) de-anonymize i.e. Tor users (unless you single out one specific target/person or theymessed up their Opsec). And that's just one "Darknet", there still plenty of other "darknets" or anonymization technics beside the Tor network. With more to come.
And that is just the anonymization part, there is still the encryption part. For example the proper use of pgp/gpg is un-crackable at the moment, Tor traffic is encrypted multiple times too, and things like Vera-Crypt for hdd and os encryption are (if used properly) un-crackable at the moment too.

My personal conclusion:
Sisgill makes bold claims that are probably just false.

Two other things I'd like to point out:

The deep web isn't equal the dark net!
The Deep Web:
90% of the internet consist of the deep web. Deep web just means that the deep web is just not accessible by the broad public and/or public search engines.

The dark nets:
Dark nets are part of the internet that provide anonymous web/data-hosting and anonymous surfing/using for it's users. Examples: Tor Network, i2p, freenet..

Terroist do NOT use the dark net and "heavy encryption" (i.e. pgp/gpg) yet!

So far only (but plenty) evidence exist that terrorists do NOT use the "dark net". Even when the media and authorities claimed, after a terror attack, that the terrorists used heavy encryption and the darknet to plan and execute the attack, it later turned out to be wrong/a lie. Unless it was already a build in encryption (iPhone, Telegram App,..since of lately Whatsapp).

This might change pretty soon, since terrorists also watch the news and if the media and authorities keep telling them that "they" use the darknet and "heavy encryption" they WILL of course look into that at some point. But at least till now they use facebook, twitter, "clearnet websites", whatsapp, telegram and youtube.