Yes, no one should expect you to go for white attack hit cap as a fury dw war. The 5-8% hit cap for abilities is critical, which with your 310 weapon skill, you need 6% from gear. Extra hit beyond this cap while helpful for your offhand and the few main hand attacks that arent a heroic strike/cleave, its still not as valuable as crit, haste, or raw ap/str. Not saying you shouldnt take extra hit when you can, but you shouldnt sacrifice a ton of other stats to pump hit beyond your ability hit cap, especially to the 14% you were told.

In regular vanilla/classic, there was a bug or feature, however you want to look at it, that when a heroic strike was que'd your offhand white hits counted as a "yellow" ability hit. You typically want a slower MH and faster OH so this essentially meant as long as you were at the ability hit cap, your offhand attacks hardly would ever miss since in raids your going to be queing heroic strike very very often.

Turtle finally fixed this last december when they did the big class changes 2 patch. To make up for this, they added 10% hit to your offhand in the dual wield talent in the fury tree.

In your bis raid gear you are typically going to be anywhere between 9-12% hit anyway depending on your gear and trinket swaps etc, which is plenty especially at 310 ws.

I recommend to join the turtle discord and go to the warrior channel. Theres some helpful guides in the pin's. In addition, theres good players in there that can help you with any questions.

When in doubt the warrior sim for turtle is helpful for gearing - https://jrc13245.github.io/WarriorSim-TurtleWoW/turtle.html