Learn Turkish: O uzlaşmaz tavrına gücendi çoğu. - Most of them were offended by that uncompromising attitude.

This is a devrik cümle (inverted sentence). In standard formal Turkish, the subject çoğu (most of them) would go at the beginning. By placing it after the verb gücendi, the speaker treats it as an afterthought. This creates a natural, colloquial flow and keeps the listener's focus completely on the cause of the emotional reaction: O uzlaşmaz tavrına (that uncompromising attitude).

How does the word uzlaşmaz become an adjective here?

It comes from the verb uzlaşmak (to reach an agreement or compromise). The -maz suffix forms the negative aorist (broad/simple present) tense. In Turkish, aorist endings are very commonly used to create adjectives that describe a permanent trait or habit. Therefore, an uzlaşmaz attitude is one that habitually never compromises.

Why does tavrına take the dative case ending instead of the ablative (from/by)?

The verb gücenmek (to feel hurt, to take offense) dictates this. In English you are offended 'by' something, but in Turkish you take offense 'to' something, which requires the dative case. The word breaks down as tavır (attitude) + -ı (his/her third-person possessive) + -n- (buffer consonant) + -a (dative case). Notice that the second vowel in tavır drops out due to vowel elision when a suffix starting with a vowel is added.

How is çoğu formed, and why doesn't the verb have a plural ending?