Not true. Height of the best SFs in the nba (according to nba.com) are listed below..
LBJ-69
Durant-610
Luka-67
Kawhi-67
P. George-68
Ingram-67
Siakam-69
Tatum-68
Butler-67
Bogdanovic-68
Middleton-67
T. Harris-68
Danilo-610
G. Hayward-67
OPJ-68