Depending on the userbase (e.g. end users from non-OSS ecosystems) and what you want to achieve you might just have to accept they are more used to talking to corporate support agents than filing bugs and learn to work with them. Autoclosing immediately puts the user into an adversarial position - better would be to have an automated reply for incomplete bug reports stating what is missing and that the information is needed for you to help the user to make it clear that filling it in properly is in their best interest as well.