I (29F) am deeply resentful that my parents support my sister (32F) and I don?t know why

Both my parents are incredibly hard workers and from a young age it was clear that there were expectations to do well in school and get a good job.
I always did what I should to please them. Went to a good school, got a good job, and completely support myself.
My sister on the other hand is one of those people who is always caught up in some drama or chaos that she drags my parents into and they inevitably bail her out. She barely graduated HS, dropped out of community college after a semester. Spent her early 20s partying. She?s never been able to financially support herself so she?s lived rent free in a beautiful apartment in a building my parent?s owns.
Despite not having a dollar to her name she decided to get pregnant with a man she dated for 4 months and now my nephew is 5.
My parents totally support her and when they don?t she kinda guilts them into. My mom got herself a new car that she?s wanted for so long and my sister asked to borrow it and just never gave it back. When my mom asked for it back my sister gave some sob story about how she has a kid so she needs it more. She hasn?t worked for the last 6 years despite the fact that my nephew is in school full time but she says a job just doesn?t interest her.
I?m realizing I?m DEEPLY resentful that my sister just gets to do whatever she wants and my parents always bail her out. I asked my parents why they support her, do they think she?s mentally or physically not capable of working. And they said she?s perfectly capable it?s just not what she wants to do.
I don?t understand why my parents coddled her but it?s making me dislike all of them. My dad got mad at me and asked why I care so much and he?s right I don?t know!!!
It?s hard for me to respect her just taking and taking and contributing NOTHING to society, not even volunteering. I just see her as someone who is so entitled.
But my dad?s right, why do I care? I?m having trouble unpacking that and would love any insight.
TLDR: My parents support my sister financially and it makes me deeply resentful. Why?


Source.