If Islam strives against idolatry, can you explain why when Muhammad returned to Mecca and destroyed the false idols, he intentionally left the Ka'bah which is now centric to Islam. I think I understand that the Ka'bah seems like more of a connection to Allah though Abraham, but praying in the direction of the Ka'bah, isn't that somewhat hypocritical?
The Kaabah is a building and not an image or representation of Allah, not a false deity, and not the intended object of worship, hence it is not an idol.
It does mark the qiblah: the direction faced when worshiping Allah on earth. And this has been ordained by Allah before the conquest of Makkah and even before the advent of the arabs:
وعهدنا إلى إبراهيم وإسماعيل أن طهرا بيتي للطائفين والعاكفين والركع السجود
And We charged Abraham and Ishmael, [saying], "Purify My House for those who perform Tawaf and those who are staying [there] for worship and those who bow and prostrate [in prayer].
ومن حيث خرجت فول وجهك شطر المسجد الحرام وحيث ما كنتم فولوا وجوهكم شطره
And from wherever you set out, turn your face in the direction of the Sacred Mosque (Al-Masjid-ul-Harām), and (O Muslims), wherever you are, turn your faces in its direction
And Joshua rent his clothing and fell to the earth upon his face before the Ark of the Lord until the evening
I shall prostrate myself toward Your Holy Temple
That Your eyes may be open toward this house night and day, toward the place which You said, 'My Name will be there;' to listen to the prayer that Your servant will pray toward this place.
and spread forth his hands toward this house.
And Daniel, when he knew that a writ had been inscribed, came to his house, where there were open windows in his upper chamber, opposite Jerusalem, and three times a day he kneeled on his knees and prayed and offered thanks before his God just as he had done prior to this.
So praying in the direction of Allah's House is not idolatory.