I hate don't hate Akainu But some of his actions are shit although they are justifiable. So I will list most man reasons why people hate him and justify that....now read below why:
1. He killed a ship full of Oharians citizens that they were suppose to protect simply of the possibility of that there might be archeologists in the ship, if you are a a side that wants to win you must be willing to have sacrifices because if you don't you will never achieve anything. I'm sure most people would do the same to prevent others from finding their secrets.
2. He killed that scary cat Marine who was scared to fight, I know we've seen this many times in OP where weak willed people are killed just because they are afraid to fight... so why blame Akainu for executing a useless soldier who succumbs to fear?
3. Making Squado .stab WB...... well it is a dirty trick but more can be said about Squado... for being an idiot to take word from a marine show would do anything to win. After all Akainu uses brains in his fights where else WB was just using the the trust between them.... so why blame Akainu for using his intellect to weaken WB after all it really helped him have a chance against WB.
4. He killed Ace.... ah well Ace deserved it, why didn't he run? Why did he go back just because Akainu badmouthed WB? Ace was stupid for easily falling to Akainu's bait when he saw clearly that he can't cacthup to Ace and luffy, Luffy was smart enough to run... he always know when to run... So I think Akainu just did all he cold to kill Ace and that is impressive, he easily manipulated Ace's weakness.
Ovarall Akainu is so badass right now that I can't see his weaknesses besides that of facing just a power full opponent than him like WB.... Akainu is a great Marine in my pont of view....