UKF can deal with mg no problem. Flank it, buy sniper/light vehicles heck bren carrier can do it which you can buy at the start wth you guys smoking
Ostheer have a sniper that comes much sooner than UKF's. UKF's sniper comes around the time Ostheer would be building their 222, giving it rather a short window to "deal with an MG" (Even shorter if it's immediately countersniped by the Osther sniper)
The UC is... OK as an MG counter, but it's quite vulnerable to being zoned or even outright killed by Grenadiers's fausts, and even by the MG if it enters its arc (Especially if said MG is veterancy one and pops Incendiary rounds). It also ceases to be a threat to your MG when the 222 or PAK hits the field.
UKF also only have a single light vehicle, in the AEC... which kind of isnt an "AI" unit, and isnt really able to "deal with" an MG before itself is dealt with/zoned by a PAK gun, or grenadiers.
None of this, barring the UC (Which is sub-par as has been stated) is useful in the first few minutes, which is when UKF want to be really dealing with an MG, as they desperately want to push off their enemy and dig in quickly. What are YOU smoking?
Ostheer, in comparison, have their own sniper, which can be built from the beginning of the game (Tier 1 is not a real delay), along with a mortar, which can similarly be built from minute one... they also have the vision afforded by their Pioneers, which outranges the opposing MG's vision, allowing them to far more easily bypass an opponent's MG, and prevent their own from being circumvented through Flanking manoeuvres. "Flank it" is not an unique concept to UKF, and honestly they don't do it as well as other armies due to needing to stick to cover.