Let's not forget that criminals can also exploit a backdoor, so creating them jeopardizes public safety. Furthermore, if IT vendors agreed to create those backdoors, criminals are not forced to use those products and can still rely on homebrew or foreign tools. Later, the situation might escalate where these tools utilization is prohibited (e.g. VPN, Tor), as we see in some countries, but that shouldn't stop criminals from using them while making the public vulnerable.