0.6% of the population are lawyers. 41% of legislators are lawyers. Legislators propose, write, and vote on the laws. It's duplicitous to say that lawyers don't propose, write, or vote on laws.
As the other person mentioned, that's probably not a good idea. The people writing the laws should know about the legal framework. They should understand a wide body of legal concepts, procedure, precedent, and the appropriate verbiage.
It also ties in with the fact that, like it or not, we need lobbyists. Sure, the system is broken, but legislatures can't be experts on everything. So, they need people to explain and even be able to get into the details. They need someone who is a domain expert.
That is, theoretically at least, why we have to have lobbyists. Legislatures should also have a good baseline knowledge of the legal system, with all the details that includes. They need to be very familiar with the legal system which makes lawyers potentially good legislatures.
Potentially... Like lobbyists, there's good and bad with the system. There is potential for good, as much as there is potential for bad. We seem to like to think we are in dire straits and that doom faces us constantly, but we are actually doing quite well. We're not perfect, but we aren't as bad off as the nightly news would have us believe.
Also, people really hate lawyers, until they need one. I'm not a lawyer but I have great respect for some of them.
Congress has specialized, non-partisan staff called legislative counsel. They will take instruction from Congressional personal staff and committee staff and create drafts of legislation. At times, if the Congressional staff choose, outside counsel (K-Street) can be involved in this process. They can provide "model legislation" at the beginning of the process or suggested revisions. This can be very helpful because the K-street counsel is, at times, more expert on various highly technical aspects of the law. It can also speed up getting the bill into a finished place where it can be introduced. There's nothing particularly nefarious about this process, although well-funded, well-connected interests can get bills drafted sooner. But to be clear, Congressional political staff (who may or may not be lawyers) are in charge of the drafting process. Congress writes the laws.
