why does brake pedal feel "spongy"?

Probably need to be bled again. start with the wheel farthest from the master cylinder, then around, then around again in a different pattern

Yes, station a person who knows what the hell is going on to assist you. This is not rocket science "open the bleeder" pause pause pause "close the bleeder" pause pause pause "open the bleeder" is about the technology of a ten year old, but some people are adverse to grobblin' down on the ground with awful fluids sprayin and squirtin nearby...so as my co-hort says BLEED IT AGAIN. this time with competant help.

If the fluid level was low enough to allow air into the ABS system, it has to be cycled to get the air out. It happens if there was a major leak or if the fluid was allowed to drain when changing a caliper. Next time stick a golf tee in the hose.