My point is that people striving to be rational should bite this bullet. As you point out, this might cause some problems—which is the challenge I propose that rationalists should take on.
You may wish to think of your actions as non-arbitrary (that is, justified in some special way, cf. the link Nick Tarleton provided), and you may wish to (non-arbitrarily) criticize the actions of others etc. But wishing doesn’t make it so. You may find it disturbing that you can’t “non-arbitrarily” say that “striving for truth is better than killing babies”. This kind of thing prompts most people to shy away from moral skepticism, but if you are concerned with rationality, you should hold yourself to a higher standard than that.
Perhaps this is a known issue, but since I haven’t seen it discussed, I thought I’d mention that images don’t seem to work in some (all?) of the old posts imported from Overcoming Bias. See for example:
Timeless Physics
The first few pics in that particular post is available from an external server if you click them, but I don’t see them inline. The last picture seems to have been hosted at Overcoming Bias, and is no longer accessible.