满口脏话总比装纯好
[măn kŏu zàng huà zŏng bĭ zhuāng chún hăo]
Means 'Better to talk vulgarly than to feign chastity/inocence'. The person behind this net name might have an opinion that genuine personality outweighs hypocritical moral righteousness. Despite having impolite speaking habits, there's honesty without pretensions. This is quite unconventional in traditional contexts but indicates nonconformity against certain societal conventions.