You could just say the same about airlines: "You chose the flight connections you sell to customers. It is your responsibility to make sure that the product you sell to customers can be fully enjoyed by the buyer." Padding a connection by an additional three hours is in most cases simply not possible as you'll miss the only daily flight and you'll have to wait nearly 24hours. There are MCT for a reason.

If the first flight arrives so late that it is below MCT, it's officially not possible for the passenger to reach the next flight (even if it's Usain Bolt without any checked bags and the next flight departs from the gate across the hall). When at risk of missing your legal connection due to long security/immigration lines be active, ask to be let through, show your ticket, explain.