While you are wearing any coating... the oil and moisture content in your natural nail plate actually increases.
When you remove the enamel, you remove all of that built up moisture and oil. Depending on the removal solution and technique, you will also remove a lot more oil and moisture from the nail plate above and beyond the extra that had built up.
This can make the plate far less flexible and almost more 'sensitive' to touch until the oil and moisture content returns to normal.
The only other reason I can think of has to do with Area 51 and probes... we wont go there. :beam: