It doesn't seem like an extrapolation given how you phrased it. If you meant to say that "it is only idiocy if you don't know how to anonymize your Bitcoin usage", that is not at all how your comment comes across.
The parent comment cast the first stone by calling the bitcoin users idiots because bitcoin is traceable.
The gap between knowing enough to trace bitcoin, and knowing enough to make bitcoin untraceable is tiny, which means anyone understanding enough to know that bitcoin is traceable bit not bothering to research how it can be untraceable is an idiot (when they go online and call all users idiots, dsspite not having done a tiny bit of research into something pretty well known int the community).
Not normally my choice of words, but I chose to use the language of the comment to humble him a little.
And I was talking to the commenter directly, not generalizing to all bitcoin users. THAT IS an unwarranted extrapolation.