I actually was under the impression that we are libertarians here and we should push for any solution that decreases centralization.
No block size limit = free market decides the proper size
You mean the 3 people controlling the pools that have the majority of hashing power control the blocksize.
Actually, no. Individual miners have freedom to choose a pool which suits their interests better or simply use the P2P pool.
OR start a new pool and convince enough people to use it.
Indeed you can, but you've moved away from the standard Bitcoin model where we hold miners hostage