What? You can't read Matthew 21:13 for yourself? (where Jesus quoted the reason?)
Jesus cited Isaiah 56:7 and said: “‘My house will be called a house of prayer...’
The temple was designed to be "a house of prayer" -- not the Mormon superimposed Mormon temple version of necro-baptisms, marriage & generational religious rites (sealings), etc.
Do you really think Jews baptized the dead in those temples? Or had children "sealed" to them?
Utter nonsense and not Biblical. You can pray anywhere and Israel has. Check God's own words in Ex. 25:8 or John 2:16.
You're taking the verses out of context, per usual. Recall that the Pharisees and Chief Priests of that day demanded a miracle to prove the authority of Jesus Christ to act in his Father's House, clearing them out. He then explained his coming death and resurrection. That incensed them as their apostate status had lost the truth by that time. They were utterly bling to the truth that stood clear as the sun before them.