This game has been around for a LOOOONG time, and lemme tell ya over the years it's had some ups and downs. It's mainly the community that's a problem, along with trashy events, scammers and more... I'd know because I've played roblox for nearly 3 years. I wouldn't reccommend letting your child play this without keeping watch on what they're playing. Here's some tips if you run into anyone who's disturbing you in a game:
-Just quit the game, they can't follow you.
-Block them.
-You can report them, but some people say it doesn't work so i'd reccommend the option above.
Conclusion: It's OK, just stay safe from others and let your imagination run wild!