Why Do My Character Always Have Mining Fatigue?

Weapons have certain attack speeds (slow, normal, fast, etc), and in game this attack speed is actually the mining fatigue effect, but the texture pack changes the name "mining fatigue" to "attack speed". So if it says mining fatigue for you maybe you don't have the texture pack?

 

Depending on the weapon's attack speed (ex: slow, normal, fast, etc.) you might get mining fatigue IV, or mining fatigue II, or even no mining fatigue at all and get haste or haste II instead. If a weapon has an attack speed tier identification it'll increase your attack speed, and in game, with the texture pack, that attack speed will change from red attack speed (usually associated with slow attack weapons, but it can appear on normal attack weapons as well, and without the texture pack it shows as mining fatigue) to green attack speed (usually associated with fast attack weapons, and maybe without a texture pack this is haste? I'm not sure though, since I've never tried to play without a texture pack).

The attack speed of a certain weapon isn't always directly associated with a certain mining fatigue effect (for example: if I have a weapon with normal speed will I always get mining fatigue II? No, it can be mining fatigue IV or something else, it depends, but if it says on the weapon's description that it's attack speed is normal then it'll always attack at a normal speed (from what I've tested in game), even if it says on your screen that you have mining fatigue IV, I know it's strange... I don't understand how these mechanics work, that's just how it is...)