I have done quite a few security vetting applications for the Police down under. I can't speak for your part of the world but a single instance here would not be that bad..background checks go into a lot of detail..disclosing that offence will probably be cause for a bigger dig at your background and any associates that you may have been around..that is what causes most of the problems..the people linked to you in the database.
All you can do is apply..be honest and get an outcome.
As for the bashing..having dealt with a huge variety of people in my time..people make mistakes..good people make mistakes..none of know the background of the OP misdemeanor so we are all just speculating.