I think that's fine as long as that is communicated. Maybe this whole thing is just a failure of communication at some level. Re-reading the OP, it sounds like parents were under the assumption that to get on the ballot, a scout simply had to meet the qualifications, those qualifications seemingly being the more quantifiable stuff, rank and nights camping.
If SM recommendation isn't viewed (or communicated) as a "requirement" to get on the ballot, it could just be a matter of making that clear.
Again, if this is presented as "no first-year scouts allowed", that doesn't speak to the S