It doesn't make much sense to me.
Tom's a cop. Sure, he's a small town cop, but he is still a cop. Google told me the average salary for an American cop is $59,196 per year. (Entry level positions start at $45,831 per year, while most experienced workers make up to $88,313 per year.)
So why does Rachel think he is bad for her sister? The animosity seemed to be before he showed up at her house with Sonic.