Current and Resistances
I think you're confusing different meanings of the word "same".

In a simple circuit - one with no branches - the current at any point in the circuit is the same as the current at any other part of the circuit.  Current isn't "lost" in a resistor.

But if you add a resistor into the circuit, then it resists the flow of current, making the current drop.  The current at any point in the circuit is still the same as the current at any other part of the circuit.  But it's not the same as the current was before you put in the resistor.