Yes they are, roads are mostly build and maintained with taxpayer dollars.

So cyclist only use a portion of the road, don’t generate any wear unlike the other 2 tons vehicles they are sharing the road with but still pay the same amount than car users.

You are right that it is quite unfair.

https://www.urban.org/policy-centers/cross-center-initiatives/state-and-local-finance-initiative/state-and-local-backgrounders/highway-and-road-expenditures