Personally I hate it when bikes are on the road in an area without bike lanes. Do I try to pass them? Sometimes they're in the middle of the lane. But other times they're off to the side, sort of in the lane, but not completely. I might risk hitting them if i try to sneak past, but if I dont pass them then I have to putt along behind them at a snails pace cus they can't do the speed limit.
Regular bikers know to use hand signals to turn but tons of bikers don't use them at all. And you don't always know what kind of biker you're dealing with. though a good sign is if they're wearing a helmet or not, cus generally the more responsible-behaving cyclists will wear proper protective gear. But thats not always the case, and plenty of places have different rules about what's required in that department anyway.
like for instance Punjabi/Sikh people are the largest visible minority in my city, so there are regular legal battles against them wearing helmets because they need to wear their turbans (and you can bet the bigots in the community love to voice their opinions on that). Also there are the people who just don't care what they're required to have, since it's rarely enforced anyway.
IMO If you can't do the speed limit you should NOT be in a lane with a vehicle that can. We already have a place for modes of transport that can't go fast enough. If there are no bike lanes they should get on the sidewalk and yield to pedestrians. Which is easy to do since there are generally fewer pedestrians than there are cars. But plenty of people also think that bikes should NEVER use the sidewalk and should only be on the road. It really depends on where you live.
In Vancouver there are tons of bike lanes and a well integrated cyclist-culture, plus in the downtown areas the sidewalks are generally way too busy with people to bike on them. But in Abbotsford (where I live) the city is really spread out and suburban and our transit system sucks, so everyone drives everywhere and there are very few pedestrians. there also aren't many bike lanes so biking on the sidewalk would be extremely easy. Also there are park paths cutting through most of the city so if you're on a bike you can often use those as shortcuts and stay away from the road completely for big chunks of the trip (depending on where you're going).