So the second kind of people may actually include just Anne Curzan herself and a very few others capable of viewing language more objectively, not in terms of what's right and what's wrong but rather in terms of what works and what doesn't. The purpose of language is to communicate with others. If what you say communicates your message clearly, that's what counts, not your particular word choices or grammar.
Of course, I've noticed that Curzan, Steven Pinker, John McWhorter and others in this group speak and write in ways that would win the seal of approval of English teachers anywhere. They know the rules and follow them, even though they may say they don't believe in them. That's because things like grammar rules, standardized spellings and widely accepted definitions are what make language work. We couldn't communicate very well if we each spoke our own language in our own way.
Words constantly come and go and change their meanings and pronunciations. Verbs become nouns, and nouns become verbs. Last year's dictionary can go out of style as quickly as last year's dress. So as much as we may need language rules, we should not allow them to become rigid. The two groups of people may actually be those who stay both flexible and tolerant when it comes to language change and those who do not.