Answer

In the Name of Allah, Most Gracious, Most Merciful. 

All praise and thanks are due to Allah, and peace and blessings be upon His Messenger.

In responding to your question, Sheikh Ahmad Kutty, a senior lecturer and an Islamic scholar at the Islamic Institute of Toronto, Ontario, Canada, states:

Walking through a sanitization gates would not render your clothes or body impure. So, you need not worry about praying after entering through it.

Islam warns us against rigidity. Prophet Muhammad (peace be upon him) said, “This religion of ours is easy to practice. Whoever makes it hard will be defeating himself by his rigid attitude.”

He also said, “Woe to those who are rigid.” He repeated the words three times.

Therefore, I would urge you to shun such an attitude.

Almighty Allah knows best.