I agree, some of those home full sized acrobats have very strange looking airfoils. Some of them remind me of the old Coke can airfoil we made years ago for our funflys.
No science involved in those babies.

There seems to be a great deal of different approaches when to come down to pattern, some like them fat, others like 'em thin. There are even those that like them fat at the center cord and thin at the tip or even fat at the tip. Look at CPLR's original Synergy wing and it has a very thick airfoil at the tip. Just about everyone I know has had their own Synergy wings cut using a thiner tip airfoil! Obviously it suited him!!!
Some years back Chip Hyde experimented with a double convex airfoil. After the fanfare of trumpets had died away, seems to have decided to kick it in the head and get back to basics.
The fact that there are so many different approaches and personal preferences indicates one thing... You can get away with just about anything! One could could even start to question the actual contribution the airfoil selection make to the overall performance of today, super light, super powered pattern planes. My indoor flat foamies "fly" superbly and don't have an airfoil... not even a sharpen leading edge.
I put the word fly in inverted commers because thats not what they're really doing and it's it's exactly that what's separating our light weight, low wing loading, super powered models from full size aeroplanes.