The security and safety of almost everything relies on strong, uncompromised encryption.
There’s no way to reasonably draw, much less enforce, a line dividing licit and illicit uses.
If you compromise some subset of messages, illicit uses will just move to a non-compromised technology.
So instead of drawing a line, which is impossible (and also comes down to human judgements about things like whether gay people should be killed) the only choice left, if you insist on being able to decrypt messages, is to legislate the ability to decrypt all of them.
First of all, good luck enforcing that; second, in so doing you will sweep in a lot of legitimate uses of encryption and make people and businesses less safe by endangering their finances, their privacy, and even their physical safety.
Because once you give governments the ability to read messages even assuming key escrow entities can protect the integrity of the system (unlikely) this ability will be abused by bad governments who have records of inflicting human rights abuse on citizens for “crimes” as minor as being gay, being trans, or saying the wrong words about god.
And in addition to being accessed by the bad people in government and the bad people drawn like flies to honey to work in the key escrow organization, the escrow keys will get out and be abused by more bad people which will be an entire other level of problems.