Does Macbook Pro charging profile depends on electricity grid?
There's no "magic" involved in charging.

The standard Apple charger delivers the same voltage and amps to the laptop when used on a 120V grid as when used on a 230V grid. So the type of grid should not matter. 

20A fuses are definitely not common in all of the EU, it is much more common to have 10A fuses for lights and other outlets in normal homes, and 16A or more for kitchen appliances, etc. However, this doesn't really make any difference for charging a laptop. Even 10 amps at 120 volts is 1200 watts - which is way more than what is needed to charge any Apple laptop, as Apple's largest laptop charger is a 87 watt charger.

There's also no geographical components to charging. It is not so that the Apple charger knows that it is in Hungary and charges quickly, and knows that it is in the US and charges slowly. There's no such provision in any of Apple's chargers.

The most likely cause of your problem is that you're simply not using Apple chargers or not using the correct Apple charger. When you're in the US, you might be using a less-than-recommmended watts charger - or a knock-off charger. This would explain why it charges slowly.