Restricting internet filtering technology, just like military hardware and encryption technology, simply imposes higher costs on regimes which might not be able to afford them. It's not perfect, but a viable option if promoting freedom of expression is a policy the West wants to pursue.
The fact that you seem aware of/to be hinting at the pre-1996 Encryption Export Restrictions makes this even more confusing, since the fallout from that is well-described and broadly negative. (e.g. netscape having to ship a purposefully weaker RSA implementation, which given the difficulty of obtaining the US implementation, ended up with even _domestic_ users being compromised).
No, not only do I think it's "not perfect" I think it's overtly worse than doing nothing, given the increased legislative burdeon/pitfalls, reduced trust in US and bad optics as far as being consistent in what we stand for. Many of the nations we might most worry about have already shown that complexity is no barrier towards implementation, or else we wouldn't be having such a "fun time" with nuclear nonproliferation, something far more locked down _and_ far more difficult to implement compared to internet filtering.
I'm not going to say there shouldn't be a line, I'm generally not a fan of how much in the manner of military arms we spread around the globe, but my principle is always to err on the side of less restrictions rather than more, especially when it doesn't seem to accomplish the stated goal and in many cases will amount to cutting off your nose to spite your face, and _especially_ when it sets a precedent/lowers the bar for govt intervention.