Are they actually physically stopping you from doing it your way? Why not just tell them where to go and PROVE them wrong by training YOUR way; nothing like proving yourself right in the face of opposition. I understand the altruistic impulse causing you to want to get everyone on board the below parallel train, but some people just won't be swayed. Ask them where they get their sources.
Here are your sources, stolen from some website (exrx.net):
# Boyden G, Kingman J, Dyson R, (2000). A comparison of quadriceps electromyographic activity with the position of the foot during the parallel squat. J Strength Cond Res. 14(4): 379-382.
# Fleck, S.J. and Falkel, J.E. Value of Resistance Training for the Reduction of Sports Injuries. Sports Medicine, 3, 61-68, 1986.
# Fry AC, Smith JC, Schilling BK. Effect of knee position on hip and knee torques during the barbell squat. J Strength Cond Res. 2003 Nov;17(4):629-33.
# Hatfield, F.C. (1989). Power: A Scientific Approach, Contemporary Books, pg. 158.
# Kraemer, W.J., Fleck, S.J. (1993). Strength Training for Young Athletes, Human Kinetics.
# Kreighbaum, E., Katharine, B.M. (1996). Biomechanics; A Qualitative Approach for Studying Human Movement, Allyn & Bacon, 4, Pgs 203-204.
# National Strength and Conditioning Association. The Squat Exercise in Athletic Conditioning, NSCA Position Statements.
# Signorile JF, Kwiatkowksi K, Caruso JF, Robertson B, (1995). Effect of foot position on the electromyographical activity of the superficial quadriceps muscles during the parallel squat and knee extension. J Strength Cond Res. 9:182-187
I think the meat of those studies can be found here, haven't the time to go through it myself:
http://www.ncbi.nlm.nih.gov/entrez/query.fcgi?db=PubMed
Good hunting!