Accepting and respecting your points Amy, Consider this, if you will:
Despite the fiction, there are a few realities to consider. Charlotte Lucas is a chancer. An unfortunate contender for romance because of her unremarkable looks, she got just one lifeline and grabbed it. She was level -headed and sensible in her thinking, if somewhat devious in her wielding the butterfly net. Her thinking is clearly show by her own words:
"Happiness in marriage is entirely a matter of chance,". She sacrificed happiness for security. No one can seriously blame her for what she did. Lizzie was wrong to blame her simply because she concentrated on the goodness she knew in her friend being worth a great deal, but should also have considered how few Charlotte's options really were in a place like Meryton. Jane was 23 without offers, she herself was 20 and her only offer so far was from the man she refused and Charlotte accepted. Charlotte had reached 27 without any success even with the "step-below" class of farmers, clerks or merchants. Even the local militia involvement had seemingly been indifferent. There weren't even enough men to dance with at the local ball-hop. Bingley and Darcy were like "pennies from Heaven" in a wilderness of romantic opportunity cum security. Charlotte was never in that particular frame. She did the sensible thing and played the percentages.
"Mocking" a word that can range from lightweight mickey-taking amongst friends that has no real detrimental intent, to cruel, selfish scorn akin to almost to hatred. What is Lizzie doing when she sanctions Darcy in front of Colonel Fitzwilliam? Is that not a form of mockery? Mr Bennet uses sarcasm on several occasions. That also is mocking his neighbours. He even mocks Charlotte when he learns of her acceptance of Collins. He mocks his wife and daughters but there is no hatred there. If Charlotte actually agreed with some of the nonsense her husband spouted, then she would go down in everyone's estimation, I'd say? One can mock with a glance without saying a word.
I quite believe (personally) that Mr Collins's servility before Lady Catherine would always be a source of embarrassment in any sensible woman as it obviously is in Charlotte. I also believe that Lady Catherine would choose someone like him to give a living to because of the same servility (but that's another story)
Amen. (-: