They are right...I started shooting in the 60s and I've had guys make all kinds of claims about broadheads and all type stories of arrows flying funny...
We are actually lucky to have as many good heads as we do, some heads were really funky back in the 70s...If you are shooting the correct spined arrows your bow can be tuned for a variety of broadheads...
Take your bow out and shoot a group with field points, mark the group...Now screw in your broadheads and shoot a group...If the group is high or low or left or right then you need to move the arrow rest just a tad...Work on one at a time, when you finish you should have field points and broadheads hitting at the same point...
Google Easton arrows and they can explain in more detail but it is truely that simple...Some guys tweek their nocking point but for most of us the rest is easier to play with...I'm only talking about moving it 1/32 or so to change the point of impact 2-3 inches at 20 yards...
This also helps your bow transfer more energy to the arrow...Now once you are finished you can decide what type broadhead you want to use, but never let your out of tuned bow dictate what you have on the end of your arrow...