Why is it that every one brags about how easy it is to kill a 'lala' and everyone asks for it to be perked?
 Simple, dedalos. 
 Claiming the La-7 isn't that of a big deal is the only form of solace one can expect when facing this plane. The bare truth is in what Urchin said;
Actually, I rarely kill La-7s in LW planes. If I drag one away from their horde, they just run if they lose the advantage. If I meet one who has any idea at all how to fight, I die.
 People who claim the La-7 isn't much of a big deal, constantly drags in the human factor into an objective performance analysis. But if we reverse that logic, it should mean, 
"the only way to win against a La-7 is by having a truly superior advantage in pilot skills" <- this is a really big thing in the MA, considering "average" or "unimpressive" pilots like me take up more than 80% of the population. 
 Given the circumstances are right one can kill a Me262 in a A6M. So, should these special circumstances with special conditions(ie, "pilot factor") mean anything? 
 I mean, nobody takes the "pilot factor" into consideration when they talk about other perked planes. F4U-4, Spit14, Tempest, Ta152 etc etc.. will these planes be overwhelmingly "problematic" to be considered "uber" if they are unperked?
 Ofcourse not. People who laugh at the La-7 will laugh at those planes too, if they become free planes. They'll brag and boast about how easy it is to kill these planes in a 1:1 fight in their slower planes. 
 But really, what kind of a stupid would want to engage a Spitfire or a slower mid-war plane(that usually maneuvers better) in an all-out 1:1 battle?
 If you look at it closely, you can see that 
"I have no problems with it" comments most usually means 
"I have no problems with a stupid pilot who doesn't know how to handle this plane". 
 So, what happens if an average/decent pilot who knows better than to stick around in a tough fight against a better pilot in a slower, but better maneuvering plane takes the La-7?
 Logically, they "extend", "run", "bore and zoom" and etc etc.. Ofcourse, no amount of superior skill can catch a La-7 doing that stuff in a slow mid-war plane.
 So, they choose to ridicule it as "cowardice". 
 So the overall score is something like this;
* In some cases they find a stupid La pilot and shoot him down, they brag about it. 
* In most cases they find an average La pilot who they cannot shoot down because of its pure performance, they decide to ignore and belittle it. 
 Ofcourse, it doesn't take a brain surgeon to figure out that the second case is which proves how formiddable this plane really is, not the former.