Look at the language of that page. All the statements are without certainty, eg it's not "an adversary cannot identify them" but "an adversary cannot identify them easily."
Yes, the tor project is very transparent that anonymity is not guaranteed. Bridges and obfuscation tools are simply one possible answer to the "how is [connecting to tor without ISP detection] possible?" question.
The linked article tries to imply that Ross Ulbricht's arrest was somehow the result of deanonymized tor traffic, but in reality many (most?) large DNM [1,2] and malware/hacking arrests seem to be the result of poor opsec [3].
Obfuscation is a cat-and-mouse game and with enough resources, it's always possible to detect. While Tor is OK for privacy from your ISP or the big-tech firms, certainly not for what the OP described. I think recommending Tor as the definite solution for these types of people is irresponsible.
If you ever see security software that promises absolutes, you should view it like an investment opportunity that allegedly only goes up and can't possibly go down (i.e. you're about to lose all your money)
