That must be the stupidest thing I have heard in a while. TPS does not restrict travel. Its just common sense to not travel frequently while on TPS because the whole point of then granting us TPS is because its not safe for you to return to your country. At the worst, CBP will ask you why you travelled(in a contemptuous way) but that's it. As long as you have your travel document and its valid and you are not doing anything fishy or travelling to a restricted country, no one will deny you entry. Just make sure not to travel too frequently and stay outside US for long period of time as this can potentially affect your TPS renewal.