I saw one guy argue that Bitcoin cannot work because military intelligence has equipment with which it can read what is typed on keyboards located inside buildings from vans located outside.
It's true that keystrokes can be recognized from a short distance making it possible to see what someone is typing on a keyboard inside a building.
https://cse.msu.edu/~alikamr3/pdf/jsac2017_doublecolumn.pdf
But that is not an argument against Bitcoin in particular. What it may be is an argument against using your cryptocurrency wallet when there is a suspicious looking van on the street just outside your home. :D
Another guy produced word salad containing the phrase "information theory" to prove that Bitcoin's encryption cannot work.
You know someone hasn't got a single bitcoin and that they may be a just a teeny bit salty because of that when they start presenting arguments like that.