For better or for worse, the pricing at monuments is different for Indians and for tourists considering the purchasing power of each. Spending $3 on admission for a western tourist is not that much while Rs.140+ (USD 3) for the average Indian is a substantial chunk of change.

Here in NYC, I know some people who were once complaining to me about the disparity in such pricing for Indians and visiting foreigners. Later the same day on a visit to the Metropolitan Museum of Art, the same gent insisted on paying full price admission for me (Recommended admission is ~USD 14), when I was paying my token $2, that I usually do. I let him pay.

I guess folks get irked by the discriminatory pricing on the principle of it, in India, rather than understanding the socio-economic circumstances that the policy is built around.

BTW, the Taj is worth it at any price.