That however contradicts the very idea of having higher speeds.
No, it doesn't.
If you encounter windshear prior to rotation, the biggest threat is runway overrun, therefore the Boeing procedure is to rotate at the actual TOW Vr, or the last 2000ft of the runway, whichever comes first.
That is the main reason for calculating both speeds.
If you DON'T encounter windshear on the runway, you may delay rotation, thus taking extra IAS into the air, where it will be beneficial in out-performing windshear if encountered.
I'm curious how many chief pilot culled robots we have in here that would hold a calculated V2+wind-shear speed right into a building after rotation during a micro burst.
None who've read the book. Windshear escape involves TOGA thrust, an initial target attitude, then whatever attitude is needed to maintain a positive climb and avoid terrain, while respecting the PLIs (which denote onset of stick-shaker).
However it's achieved, being at a higher IAS when windshear is encountered will increase your chances of surviving it.