I'd almost avoid the subject altogether. Claiming something is BS tends to produce a "what are you, a conspiracy theorist" response, and acting concerned doesn't help much either because you just add to the group think. If your goal is to redpill a normie I've had the best luck with detailing how corrupt government is, pointing out how openly they collude with large business and screw over the little guy. How the entire concept of taxation benefits established businesses and wealthy individuals at the expense of unestablished/small businesses and poor individuals. Established businesses can pass on costs to consumers, can afford to comply with regulations, even if the tax rate is exactly the same, wealthier people have a far easier time paying it. That minimum wage helps large businesses by making it far tougher for smaller businesses or start ups to compete due to labor costs. Stuff like that is far better for red pill material than trying to convince someone that something being reported on by all MSM outlets on the planet is completely made up.

That said, once you have someone generally on board with government being corrupt, that they collude with media and large corporations to expand their power and wealth, etc. Once they accept that, it is so much easier to convince them that MSM reporting is straight up fake. Trying to convince someone everything is fake BS right from the get go is the quickest way to be ignored, and once you are written off as a "conspiracy theorist" or "that guy that says crazy stuff", it doesn't matter if you say 2+2=4, they will no longer trust you.