This sounds like something pleasant has become a power struggle, big time.
Take a moment and look at this website.
http://www.betterkidcare.psu.edu/AngelUnits/OneHour/Toile...
There is a list for assessment of readiness, and it might be different than the one you have, I do not know. This list was composed for early childhood education students, and this developmentally-appropriate child-led approach has been proven successful time and again. I have worked with children for over 19 years and have seen this firsthand, which is why I post this link near-weekly for questions of this regard.
First off, you are asking him a yes or no question in regard to "does he need to use the potty" and then, instead of taking his 'no' as a no, you are getting upset with him and *demanding* he use the toilet. As a mom and a teacher, I never ask, I tell/invite them to use the toilet. There is a profound difference in these two experiences for the child. In what you are doing, asking, ignoring his input and over-riding it, you are devaluing his perception of his own needs and his ability to assess if he needs to go, and this is why you are butting heads. DO NOT ASK FOR HIS INPUT IF YOU ARE GOING TO IGNORE IT. As wives, when our husbands do this, it makes us cross-eyed and crazy, and this is what you are seeing with your son. If you are going to send him to the bathroom to 'try', then just send him, don't offer an option only to rescind it. Children will respond better to an authoratative "In a minute, we need to go potty", where you are being clear about what's happening, instead of asking him to make an assessment of what he needs, and then telling him it's wrong.
No wonder he's frustrated.
Have you ever tried to run when something was coming out of your body? I just ask, because this is your advice to your son. Chances are, this situation is so loaded for him that he's not telling you about the poop because he doesn't want to be hurt/spanked. Spanking children is an extremely distressing and angering experience for them. And you are feeding this cycle/dynamic because he's probably very angry at you for hurting him when he makes the mistake of having a poop accident. Kids have accidents.
There are always two philosophies one can apply to situations such as these: either there is a problem and we the adults must apply technique after method after punishment/reward to 'change' the child and thus, we make their challenge our problem; the other view, which I like to take, is that the child has a challenge and while we can provide support for encouraging their success, the child must be allowed to master this challenge on their own terms.
To me, in this case, that would be sending the child to the toilet once every 1-2 hours, and if they don't 'go', just follow up in a 30-45 minute window. Save the toys or whatever they are playing with in a safe place if there are other children around. Let the child change themselves if they have a pee accident, and if it's poop, have them help with holding doors open/ bags open for the cleanup (children should not be made to touch feces, even their own). And then, let them be. My observation over the years has been simply this: the more the parents try to control the child in this regard, the bigger the power struggle, the more poopy pants in days to come.
You are going to have to figure out how to repair the relationship you have with your son around this issue, and I can tell you that "let's try better next time" is a lot more encouraging than what's going on right now. Your language regarding your son as "lazy"... I would try to find something more forgiving and understanding. He's *Not yet Three*, and doesn't have any moral understanding of laziness. He's still such a young child. Can you soften your heart a bit?
I know you want the best for your son, and I know you are averse to going back to diapers. I won't suggest it, but if your son does, listen. He's going to try to get things right too. Our kids need us to have faith that they can work out their challenges. (That's from Bettelheim's "A Good Enough Parent". You might find this book illuminating.)
H.