Christianity is both inclusive and exclusive. Jesus tells us that He's the only way (exclusive):

John 14:6

6 Jesus said to him, "I am the way, the truth, and the life. No one comes to the Father except through Me. 
NKJV

Yet God provides salvation for all who call upon Him through Jesus (inclusive):

Rom 10:13

for "Whoever will call upon the name of the Lord will be saved."

2 Peter 3:9

The Lord is not slow about His promise, as some count slowness, but is patient toward you, not wishing for any to perish but for all to come to repentance.