Our/your argument goes: if you believe the democratic process is best, it doesn't follow that you can be upset with the outcome of that process... since it's the best process.
We could flip that to be relevant to me/you: if you believe the market process is best, it doesn't follow that you can be upset with the outcome of that process... since it's the best.
If someone said that to me, there are two responses I think could equally apply to the proponents of the democracy that you are directing your question:
- While our current process has elements of markets (or democracy), it's not a real/consistent/pure market (or democratic) process. Therefore, I can uphold my belief in markets (or democracy) and still be upset with the outcome of this real-life process.
- While I uphold the market as the best process to solving social/economic problems, etc, I know there have been times when I've been frustrated with outcomes. For example, there's a damn shortage of toilet paper, or 22LR ammo, or graphics cards. Additionally, I can argue markets are best while also acknowledging problems that the market hasn't yet solved: people still struggle to afford housing or medicine, etc.
I'm starting to think there is a valid counter: you can believe a process is best without believing it is perfect. There will be flubs/mistakes made based on information at the time and additional problems to solve in the future.