What were these chaps firing before they were handed a SIG-716i? Most probably an INSAS. Now let's talk about INSAS
There are numerous problems in an INSAS, from suboptimal design to pathetic manufacturing but...even on its worst day, an INSAS shoots like a laser.
It's a heavy 4kg rifle that fires a wimpy 5.56x45mm round, resulting in a recoil energy of just around 4.5 joules. Now compare that to what most Americans shoot, a M4; same round but from a 3.4kg gun resulting in a recoil energy of almost 8 joules.
For SIG-716i this recoil energy should be somewhere around 14 joules.
I guess now even you can tell who would be more familiar with the increased recoil; our grunts or theirs.
Furthermore, our shooting techniques are prehistoric. Shooting techniques play a key role in how effectively you can "tame" the recoil of a gun. This is reason why trained 3-gun shooters in USA can handle the recoil so gracefully despite being literal kids.