We recalculate ratings after removing cheaters. But there are a lot of factors which will determine whether your rating will increase after recomputation or not.
Presence of cheaters do skew ratings for people, but for some it affects negatively and for others it can affect positively as well.
If the person with rating x performed better than what the skewed rankings (due to cheaters) reflected, their rating might increase after the recomputation. This is because their performance is now being compared against a more accurate representation of the field.
Conversely, if the person benefited from the presence of cheaters (e.g., if their ranking was artificially inflated), their rating might decrease after the recomputation.
You can read more about how the rating calculation here - Elo-MMR ratings go live on CodeChef!.