"My general with both inspire and banzai stats: attack: 33, defense: 14, charge: 43, amour: 7
vs
Vanilla yari cav stats: attack: attack: 5, defense 1, charge: 25, bonus vs cav: 15, amour: 4
Result: general lost 7, vanilla cav lost 2
Please, someone from CA explain to me how did that happens?"

Ok lets see, ari cavalry have spears so generals charge is nullified, that makes it 25+15+5 to attack during charge for the yari and 33 for the general. so 45 vs 33.
theres double the yari so thats essentially twice the attack power, that makes it 90vs33 33-1 (defence) 90-14*2 (defence)
now makes it 32vs62
you seriously still confused now? yari were doing nearly double the damage with all of them attacking at once while the general unit was all over the place.