I don't think EAs handle requotes better, I think they do handle it faster.
The reason is be the amount of slippage allowed in the EA OrderSend function with an EA.
For manual click market orders, you can allow for maximum pip deviation as an option, and it should act similar to how an EA sends their order.
With that said, this slippage allotment will most likely go against you when the brokers are playing their games with requotes. It may be just they are moving the price to see how much slippage pips they can get to fill you. Most EA users just don't see it unlike the manual traders because EA users are not paying attention...it's hard when you are not actually at the screen.
I do both, and that's how I noticed the differences.