i'm a very empathetic and sensitive person who has little patience with unpleasant people
You are contradicting yourself. Someone truly empathetic would understand that behind every unpleasant person there is a relatable story that made them that way and would be tolerant to them.
Look at Parsee. Her jealousy comes from untold years of watching people have the kind of fun she never could because of being stuck around the bridge and a very understandable desire to have that eating at her all that time. And if you take her species origin into account (which is not a big stretch in Touhou because, for example, Kaguya is THE Kaguya, after all), she is stuck there in the first place due to lover abandonment. If that doesn't give you even a spark of compassion for her then you probably aren't nearly mature and experienced enough to judge people, fictional or real.
Look at Reimu. She has lived her whole life forced into a position she has no say about. Her frequent hostile attitude stems purely from the importance of it, "enemy until proven otherwise" is a stance that comes with the job. Her more senseless hostility moments come from earlier in the series, where you could take it as her still working out how far she has to go. In her idle moments she want nothing more than just being left alone, and during incidents she just wants the wrongdoers to stop their wrongdoing and nobody else to get in the way. And the incidents usually have to do with GENSOKYO'S SAFETY, mind you, so it should be understandable she's on the edge about it. Also, again, don't just ignore the times when she cooperated with and acted nicely to the youkai, which far outnumber her more questionable moments.
Look at Aya. ...Actually, your estimation of her is correct. She's arrogant and extremely ambitious, which makes her quite rough around the edges. But again, hating her is missing the point. She comes from tengu society where such attitude is intentionally cultivated, but she's about the only one of them who, instead of also being very isolationist, has a huge interest in what happens outside of it - the rest of Gensokyo. (Hatate being a very occasional distant second in that regard.) She's worth appreciating for giving her own differing insight into life out there. That is, after all, exactly why she was added to the series in the first place. Actually, think about it. She's kind of an outsider that is very interested in Gensokyo and its characters, and is very vocal about her own opinions and biases. Isn't she very much like, y'know, all of us Touhou fans? So maybe if you feel hate for her then it's just you raging at the reflection in the mirror.
