You're definitely not wrong and I totally get what you're saying... something to keep in mind is that fact that in most cases (especially on good weather days) those training aircraft are operating under VFR as well. Even if they are IFR, they'd still need to coordinate with VFR traffic at the airport via the CTAF in Class G/E airspace. IFR aircraft don't have any sort of "bonus" right of way over VFR aircraft in Class G/E airspace. Flying an practice instrument approach in VFR is no different than calling a 5-10 mile final in VFR. Either way if they’re screwing up the natural traffic flow/best wind runway, I’d call it rude.
Right of way rules:
https://www.law.cornell.edu/cfr/text/14/91.113Definition of Final IFR approach segment:
http://www.faraim.org/aim/aim-4-03-14-6 ... a%20missedI looked at the approach charts and found the following distances from the end of the runway 31 at KMWL for the final approach fix for each:
GPS Approach 3.6 NM
ILS Approach 4.6 NM
VOR Approach 4.0 NM (MQP VOR)
Basically, if they are inside of a 5-mile final it's probably not a great idea to depart head-to-head with them. If they are still in a hold or outside 5 miles it should be OK if communicating on CTAF. Make your presence known on CTAF (and why, i.e. winds on the runway) and if they're not jerks you'll probably find in most cases they will accommodate you. If not, maybe have a chat with the airport manager to make your concerns known. Chances are you won't be the first person to mention it and maybe they can raise some stink about it.