It's funny how people like to believe what you hypothesize without anyone having some solid proof.
That is just proof how good the populism of Trump and the likes is creeping into your minds and stops your ability to think rationally.
Heavily militarized borders with everything technically possible defending them, regardless of inhumane it was/is, yet didn't stop people from attempting to cross and actually crossing.
Even the great wall of China isn't a good example because afaik that wasn't built to stop immigration, it was built to stop raiding parties.
Even the least intelligent human knows that.
The term "illegals" is misleading because they don't do anything illegal when they try to find a future for their family that is worth living.
The USA is founded by migrants so there is not even a real "US-citizen" by DNA, color or whatever. The same goes for Germany and other countries - they where founded by immigrants which is consistent with the ongoing migration of mankind.
You fail to see my point because you don't want to understand it. So much is obvious.
You are conflating immigrants with illegal entry. There's no problem with legal immigration.