It sounds like gubernatorial candidate Dean Martin wants to take Sheriff Joe's idea (which has already been implemented for prisoners who are citizens) and go statewide with it.
The only difference (from the OP's article) is that the new tent jails will be for illegal immigrants who have been convicted of crimes. The article does not state whether or not their only crime is being here illegally.
If it's good enough for citizens, it's good enough for illegals. However, there should be safeguards in place to prevent prisoners from harming each other, and to ensure that they remain healthy.