It's a sad fact of our world that many very nice people from other countries want to come and live in the US and Europe, because we're rich and have jobs they'll do. Up to a quarter million of them a year stay in the US without rights. How many consulates do we have? How many people is that per consulate per day asking for visas who will overstay?
Of course the staff sifting through applicants becomes jaded. Of course it is most unfortunate that this attitude affects legitimate visitors.

Without taking sides on the immigration question: we should understand that the citizens of the US elect Congresscritters who write laws these consulate staff are supposed to enforce. So who is ultimately responsible?

"We have met the enemy and he is us."--Pogo