No, this isn't just you. I got the same feeling, but it was kind of always there since I discovered the site. There seem to be many who include relationships, mainly based on sexual encounters into their definition of poly. I never understood that but it was somehow 'the other side of the scale' if this makes sense. Some people (for example) do have 'relationships' I personally would never call anything like that, but that is again just my preference and my way of defining what a relationship is. There seem to be some kind of 'poly' I wouldn't personally call poly myself. For me, a relationship based on sex does clearly belong to the swinging department.
Facts: 30, female, bi, v-type relationship with Sward (husband, straight, mono) and Lin (boyfriend, straight, mono), poly-fi and co-primary.