Instead of using "crap" or other similar words, try to be more specific and descriptive in your language. Here are some alternatives, depending on the context:
If you are talking about treatment:
* They mistreat them.
* They are unfair to them.
* They disrespect them.
* They abuse them.
* They exploit them.
* They take advantage of them.
If you are talking about quality:
* Their work is substandard.
* Their product is faulty.
* Their service is terrible.
* Their performance is disappointing.
If you want to express a general negative opinion:
* That's awful.
* That's terrible.
* That's really bad.
* That's a shame.
* That's unacceptable.
By choosing more precise and respectful language, you can communicate your message clearly without resorting to offensive or hurtful words.