Not true in my opinion. I haven't had any trouble telling the general class of a given vehicle from any visual range, and barring very similar vehicles like the T-72 and T-80 I can tell the exact model way before I'm in weapons range.
Resolution aside, a properly configured FLIR output goes far in identifying targets, since the default 4 gain/4 level often results in blobs with little to no discernible features other than the outline. I usually set them to about 5-6 gain and 2-3 level in clear conditions day and night, inclement weather may require different values from time to time. This provides a nice contrast for even smaller details like ERA-blocks, FCR's, armament and other turret features, wheels, rollers etc. that can aid with identification.
