they strangly have 61s mods in them end rest of gear mix of 69/72
Assuming that by "mods" you don't mean mods specifically, but enhancements and armorings too, there is nothing strange about it.
If the 72 enhancement has bad stats in it (the most obvious but not the only example would be a piece of "tank" gear with alacrity on it) then even a 61 enhancement can be much better.
Likewise there are specs for whom 61 armorings with set bonus are much better than 72 armorings without set bonus.
And so on...
I find it much more strange that there are people who don't use the low level stuff when it is better.