There will always be players who are racist.
@Camezonda said that players don't get away with it. This means that they can not so such things without a punishment (mute or ban).
If you see someone who is being racist, insulting or offending people, you could give him warnings. If you gave him 2 warnings
and he continues, you may report him on the forum. ( I can not give the link since I am typing this on my phone )
With saying "You should join Mineplex.", he means that if you like Mineplex better than Cubecraft, you should go there instead of complaining on Cubecraft about their punishment system.
In case you did not know yet, they are rethinking the punishment system. It will be better than the current one, as there will be one-day bans for teamers/cross-teamers and from what I have heard, the option to permban players (mostly hackers) will be added as well.
Sorry if I made typos or if anything went wrong with this reply. It was a pain to write this on my phone, lmao.