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.