The body of Christ, the church, is made up of many parts: some are strong older and well-taught, and others are young untaught new members called weak parts (Romans 14:1 -15:9). The well taught mature Christian is to receive and be gentle with newcomers from different cultural, ethical and religious backgrounds.
Some things are neither right nor wrong in themselves such as (1) what you eat (meat or vegetables. Acts 10; I Cor 8), (2) special days you observe (birthdays, holidays, reunions. Gal 4:11; Col 2:14-17), (3) and other matters where the scriptures have not given specific regulations: church houses, modes of transportation, worship singing in harmony or unison, color of clothing to wear, etc.
There are other things where tolerance would be disobedience and cannot be allowed because the Bible has clearly specified the right way: (1) worship assembly for the Lord’s Supper on the first day of the week (Acts 20:7; I Cor 11:17-30), (2) baptism is immersion of adult believers (Acts 8; Rom 6); (3) sexual immorality not tolerated (I Cor 5), hypocrisy is strongly rebuked (Gal 2:11-16), etc.