Sam,
I don’t train in Aikido so I hope you don’t mind my cross-threading (pun intended). Anyway, I have run into this also and so has my instructor. We simply tell them that your old art is what it is; this is how we do it here. If they want to train that is fine but keep the comments to your-self if they keep it up they are asked to leave and rejoin their former art. I find it very distracting to have someone question what is being taught and place doubt in other student’s minds. As we all know all our arts have different theory’s. It’s ok to see which one works best for you but, don’t go disrupting a class. Just my two cents… back to my own threads.
All My Best,
Todd Wayman
"…since karate is a martial art, you must practice with the utmost seriousness from the very beginning."
- G. Funakoshi, Karate-Do Nyumon, 1943