Right, but you can just click on each squad in turn to suppress them (if you right click on the ground by mistake, you'll pack the MG up, so use the hotkey for attack move which won't do that). In general of course you have to be a bit smarter where you set it up, or use another unit to extend the vision range, or have some other squad nearby to come deal with any squad that gets through without having to retreat the MG - nothing in CoH2 is a 100% guaranteed counter to anything else, but 60% of the time it works every time
*module you try and click dies*
*MG begins to pack up*