Oh, I'd say secular Jews are still Jewish. Gosh, I hope so, or suddenly I'm not Jewish. I don't attend synagogue much and stopped keeping kosher when I left my folks' house, but I still feel I'm a Jew. Thing is, the sects in Judaism are a lot less clearly defined than those in Christianity, so essentially you can almost shuttle among them depending upon how intensely you practice. I was raised in the Conservative sect but practice so little these days that I should probably be called Reform although, at the last Bat Mitzvah I was at, it all came back, reading Hebrew, singing prayers, etc.
Went out with a guy in college who was raised Reform, his father had become Conservative in his (the father's second marriage) and my ex's older brother had moved to Israel and become Orthodox. So three very closely related men, a father and two of his three sons, were in three separate sects. This is not unheard of.
As for what Jews think of Christians, I can only say what I think since, of course, I can't speak for anyone but myself. They're people and I like to think I treat people as individuals and think of them specially and individually. My only concern/peeve is people trying to convert me. This hasn't happened much since I graduated college (over 20 years ago), it's not like this is something I contend with every day, but I would and do consider that disrespectful of my beliefs and decisions.
Oh, and I should mention, I suppose, that I am related to more than one non-Jew (they all seem to be Catholics but that wasn't by design as none of these folks are related to each other, except through me).
My sister-in-law is married to a Catholic man and they are raising their son Catholic. My cousin M___ is now divorced from his Catholic wife. Their sons have been raised under both traditions but I don't know what their sons' personal beliefs are (we don't see these people too often). And my cousin A___ is married to S___, they have two kids and two grandchildren and their children were raised Jewish but I think their daughter does not practice and I think the grandchildren (they are the daughter's kids) aren't being raised as Jews. But I love all of these people; they're family even though last month they had trees instead of or in addition to menorahs.