I will start with the quote from anticommunist Polish general Anders: "Uprising was aimed militarily against Germans, politically against Soviets and really against Poles" because he nailed it.

So, it was part of the operation "Burza", a large scale uprising coordinated in entire country by Home Army. Plan was to time it between withdrawing Germans and advancing Soviets, so to present the latter ones with already organised bourgeoise Poland structures (so a pipe drream even if successful). Home Army of course failed, they only known how to do nothing, and so the operation was launched in but few places and whenever it succeeded the effect was zero because Soviets just nodded their heads, disarmed the HA and moved further.

Now even that was only possible because Soviets were doing operation Bagration, the biggest military offensive in history up to date which completely broke the back of Wehrmacht and send them fleeing west in may places faster than the Soviets could advance. But that operation ended before taking few strategic and strongly defended places like Warsaw, Kraków and East Prussia. Soviet armies stopped to replenish losses and supplies and prepare for the next offensive. They were in no condition to assault major city, which was defended by river, and fortified and manned by numerous veteran German units of Wehrmacht and SS (including some of the worst butchers like RONA and Dirlewanger Brigade, all commanded by known mass murderer Erich von dem Bach-Zelewski).

So in that conditions, command of Home Army, with general "Bór" Komorowski, without orders from his government and against all recommendations started uprising in Warsaw, in which insurgents would be horribly undermanned and underarmed. And it ended with one of the biggest singular massacres of WW2, comparable to Rape of Nankin.

So, back to Anders and his quote, uprising was aimed:

• Militarily against Germans, because obviously they fought Germans
• Politically against Soviets, and this was the crucial point, with how Soviets were breaking Germans, entire operation and uprising was needless, hard to tell how it would happen in hte next offensive, but even hardest city fights in Gdańsk and Wrocław didn't ended with even fraction of the civilian victims. No, it was all because the fucking landowners (Komorowski and a lot of higher HA officers were from aristocratic families) pipe dream and anticommunism, even Ustashe sympathiser like Anders bashed them for that.
• Really against Poles. They just knowingly went with insufficient numbers and arms and thrown the capital with all its people at the mercy of nazi butchers which already were known for having the blood of millions on their hands - and it's not generalisation, those very exact people who were garrisoning Warsaw.

The timing was the mistake, the Polish Home Army started the uprising in August of '44, but the Red Army wasn't ready to assault the city until January of '45. The Nazis basically tried to kill everyone in the city in retaliation.