USF Rifles have AT-Grenades, Frag Grenades, Bazookas, BARs, M1919s, and Smoke Grenades that nullify MG positions.
Really, we have a AT-rifle nade that has a huge delay and a very small chance of actually damaging the engine unless you can get infantry directly behind a tiger which they are not going to let you just walk up behind it not to mention the power of the tiger wiping your squads trying to do that. They can also escape from being rifle naded by using blitzkrieg or at least getting far enough behind there lines before the nade actually hits the tank.
The sherman smoke has a delay that cannot protect the tank properly (i.e. by the time the smoke lands whatever AT elements are firing at it will probably have time to take another shot, also the smoke can only block because it is ranged about 30-40 degrees of arc around the tank unlike the axis smoke which gives full 360 degree cover.
Bazookas are shit and have terrible pen against axis armor. You have unfair hand cannons that can insta salvo all USF tanks.
As for bars you have the MG42 its just as good maybe better.
And smoke nades that nullfiy mg postions? most smart players I know will move back there MG as soon as they see the smoke nade go off or just retreat.
Completely agree with original poster. Axis indeed have too many easy buttons and the majority of the tools they have are simply better.