As the saying goes you get what you pay for.
The question you need to ask yourself is...do you buy a cheap card reader that overdraws current on a standard USB port risking damage to your expensive laptop...or buy a better made card reader that doesn't do that.
Adding a resistor isn't going to do squat, it will probably result in more current draw due to lower voltage on any DC-DC converter for 3.3V, 2.5V, or 1.8V that is in the card reader. (Maybe that cheap chinese product uses 5V parts so it gets hot).
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What kind of measurement is that 0.7 to 0.9 mah
that is not a current measurement.
And if you meant 0.9mA then the power dissipation on 5V (USB) is only 4.5mW, which won't be "hot".