It certainly has the potential. One thing we can be sure of is scope and definition creep. First it will be pretty unequivocal stuff, then borderline and finally whatever they decide needs to be covered for whatever motive they find.
On the other, it wouldn't be too hard to build some reasonable safeguards into a law like this to protect against obvious abuses while still maintaining the ability for small actors to safely hit back at large ones violating the clear spirit of it.
I think you're glossing over the entire point of why people are concerned. It _would_ be incredibly difficult to add safeguards.
As a side note, you should be aware a Slippery Slope Argument is not necessarily a fallacy. Whether it's a fallacy depends on the strength of the chain of conditions. I'm not normally a Wikipedia fan but their article is reasonably good: https://en.wikipedia.org/wiki/Slippery_slope