I consider myself a proponent of parallelism, which I suppose agorism would be considered part of. The issue I find with it is two fold.

I'll expalin both briefly.

The first being that just moving outside of the current system doesn't solve any of the problems that have arose out of capitalism. Just living with your friends in the woods won't stop capitalism rampant destruction of the biosphere. You can't get away from the reality that we encompass.

The second being is it denies the interconnectedness that individuals have. Even if you manage to move away from society and build your parallel economy, you'll still be dependent upon the capitalist mode of production. The tools you bring with you would have been manufactured in the capitalist mode of production, etc.

All in all I find much of the Market oriented Anarchism to totally miss the point. If we don't challenge and change the superstructure of society directly, it won't change at all and Markets themselves are in large part of the reason why the planet is in such disarray.

Idk, maybe I'm arguing against a straw-man, but I hope I've conveyed my point articulately.