But why assume that an honest answer to those questions will make you feel better, rather than worse?

I think it's not that an honest answer will make you feel better. It's that a detailed honest answer is more likely to help you find tools for improving your situation, while a generic honest answer will make you feel bad and very little else. It's really just general steps for solving any problem.

Unattractive people have a much harder time finding romantic partners.

Much harder doesn't mean impossible! How much harder is it? How many people that look [a certain way] have partners and how many don't? Where did the ones that do have partners find their partner? Maybe you could look there. What other personality traits did they develop that helped them succeed at dating while looking [that way]? Maybe you could work on those!

And the partners they do find tend themselves to be unattractive.

This statement really requires data. Unattractive to whom? Probably not to them.