Your argument lacks any nuance, to the degree that it makes it flat out wrong.
No one is suggesting regulating truth generally, but rather specific cases that are deemed dangerous [0].
Now, you could make a slippery slope argument starting from there and that would be a valid, but different discussion.
The slippery slope argument sometimes applies and sometimes it doesn't. It depends on the specific situation. There are examples around the world of governments that very selectively suppress narrowly defined types of speech, in order to protect other values believed to be equally fundamental, but defend the freedom of all others.
[0] Within the bounds of the freedoms that a private company has to operate as it sees fit, or by means of democratic decisions.
It's true that the US government has always compelled private platforms to remove speech if it is illegal as determined by the legislative branch or common law (e.g., hosting child porn). What's unique about the current situation is that what's being censored has direct influence from non-legislative bodies such as the executive branch and the CDC, and what is out of bounds lacks specification and is subject to change according to the whims of a small handful of people.
This is a big change because the legislative body is significantly constrained in what it can censor through multiple mechanisms. The slippery slope concern falls flat in that old context, but not in this new context where 1 or 2 people (who we don't see and who may not have even been directly elected) can label something as misinformation and have it scrubbed.
I think I see what you're trying to say even if you're doing so very obliquely - the point is that this never was and never will be an issue that it makes sense to think of in absolutes.
Speech has never been free in this absolute sense anywhere, because, at the very least (!), there are cases where speech has obvious, immediate, terrible consequences.
That means that the difficulty lies in figuring out where exactly to draw a line along a blurry boundary. Hence the slippery slope issue.
No one is suggesting regulating truth generally, but rather specific cases that are deemed dangerous [0].
Now, you could make a slippery slope argument starting from there and that would be a valid, but different discussion.
The slippery slope argument sometimes applies and sometimes it doesn't. It depends on the specific situation. There are examples around the world of governments that very selectively suppress narrowly defined types of speech, in order to protect other values believed to be equally fundamental, but defend the freedom of all others.
[0] Within the bounds of the freedoms that a private company has to operate as it sees fit, or by means of democratic decisions.