This is wrong on many levels. Assuming both parties are of equal skill Panzer IV should come out before Sherman does or at about the same time. If they choose to go M8 Scott first then they leave themselves open to get dived by my tanks. If the Whermacht player has no tanks out on the field before USF can manage to get Double M8 Scotts then he probably already lost well before that point. I personally have never lost to any USF player who made M8 Scots pre-nerf or not. Are they annoying as hell? Sure but so were Soviet Clown Cars back in the day with Snipers in them and people cried nonstop about how overpowered it was yet it never stopped me from winning. It was a L2P issue. After nerf M8 Scott just tickles my units and is nothing but a glorious smoke thrower.
The issue wasn't USF rushing M8s, it was them getting them later, especially in team games. By mid/late game the dual scotts could be defended by M36s, SU85s, Fireflies, etc. at which point they were untouchable via tank rushes (at least, with favorable econ outcomes). The obvious counter to that defensive tank line was Schrecks and Paks, but double Scotts countered those very well when used correctly. The game needs to be balanced (to some degree, anyway) in all modes, and double scotts were a serious problem in team games.
As for your experience, or sov clown cars; that's fine. However, many other players at both higher and lower levels had problems with it, and more importantly, it was incredibly 'un-fun' to play against; "This is miserably oppressive but I can still win against it" simply isn't good game design.
Second why are people making LMG Grens vs USF without grabbing Ambush Camo, G43 or Veteran Squad Leaders? These are significantly more useful vs USF as they can protect your MG from flanks all game while also being significantly more mobile than LMG Grenadiers. If they are spamming LMG Grenadiers and getting owned by M8 Scotts then they deserve to lose. Different commanders are good/better vs different factions (shocker). Even pre-nerf M8 Scotts were never scary because of the timing that they come into play when you are (should be) shifting to tanks at that point. Mortar Halftrack, Regular Mortar, or even Pak Howitzers are more dangerous than M8 Scotts due to the timing that they arrive.
CoH2 is balanced around stock roster vs. stock roster, with the doctrine abilities adding flavor or countering other doctrine abilities. The goal has always been to make it possible for the game to be played without specific doctrines being 'required' vs. certain factions. This hasn't always been the case, as we've seen with various units and abilities, but it has been the goal; "the basic mainline unit isn't viable, you must use a doc locked unit" isn't a solution.
As for the comparison to MHTs, Mortars and Paks, the difference there is that all of them require being setup, and react to moving units quite slowly (via rotation). The Scott could fire fairly accurately on the move, and could easily react to moving units.
The over-all result was that static units, such as the MG42, Pak and LMG-gren were destroyed extremely quickly by the scott, and moving wasn't viable, as none of them can shoot on the move. Yes, there were other choices such as Pgrens and Doc-locked choices, but having effectively the entire default hard-countered by a stock unit just wasn't good game design.
As a counter example, imagine the impact on USF if the Ostwind did significantly more damage to moving units, to the point where it could wipe a vet 3 squad in less than a second. You'd be safe if you remained stationary, but then could be easily beaten by long-range units such as OST's LMG Grens or Mortars. This would be effectively the same thing in terms of design; horrible, as USF relies heavily on mobility.
Also remember when USF had double LMG and could throw smoke? (Also pre nerf M8 Scott Period) that never really changed Axis win rates as more experienced players just adapted (and made use of mines for the incoming smoke that would eventually come and Panzer Grenadiers)
Double LMG rifles were annoying, but as you said, could be dealt with; however, their existence also didn't counter an entire factions starting roster. In any event, this was also nerfed because it just wasn't fun to play against; blobs aren't interesting.
Everything you mentioned is basically people who are bad at the game and don't know or want to adapt. The fact of the matter is that M8 Scott is a trash unit in a faction that is poorly designed with an arsenal of extremely sub par units held together by bandaids and no amount of stat adjustments will fix it unless they address the root of the problem which is the poor faction design.
Just about every balance issue can be boiled down to "L2P" if you really want to, but it's not good for the game long-term. If the game isn't fun, people stop playing; so over-performing units get nerfed - especially if that performance requires very little user input to attain.
Does USF need a stock arty unit, and some late-game blob control? Sure; but not a form that can delete squads instantly with effectively no cooldown (or user input).