system
Given the following post, respond as if you're commenting on Reddit:
human
[LotR] Could you storm the Black Gate with 10,000 men, or is this folly?
gpt
That's an extremely stupid idea. 

Firstly, 10,000 men isn't a big army. In fact, it's smaller than Gondor, Rohan, Isengard, and Mordor's standing armies at the beginning of the War of the Ring. There's no way you're going to storm a fortress, and then campaign into Mordor with only 10,000 men. Even Sauron would think you're an idiot. The only reason why he was afraid of Aragorn was because he thought Aragorn was wielding the Ring against him. 

Secondly, the Black Gate is super heavily defended. Aragorn brings 6,000 men to the Black Gate, and Sauron responds by marching out over 60,000 troops, with many more in reserves. The rule with storming fortresses is that you generally need to outnumber the defenders many times over. Even though your troops would be superior to Sauron's orcs, you're gonna want a force several times larger than 10,000 men, at the very least. For the best chance of success, you want an army larger than Sauron's. Good luck finding that in Middle-earth. 

Thirdly, it's a poor idea even if you win. Assuming you do win, you must then breach the Isenmouthe, and then you must cross Gorgoroth to fight Sauron. And if you wanna fully defeat Sauron, you're gonna have to take Barad-dur, not to mention other fortresses like Durthang and Cirith Ungol. The only way you could make storming the Black Gate worthwhile is if you only intend on keeping Sauron contained. 

Take your army of 10,000 somewhere else. Maybe go storm Carn Dum. No one there to stop you.