No, not all parents who say they are home educating are abusers with a criminal record - BUT - there is no difference legally/practically between anyone who is doing it as they should and somebody who isn't - if the LA knows of them at all, which isn't a legal requirement at present.
The DBS might be useful in picking up the other adults in the home as well - you know, the ones who have joined the family at a later date and all too often turn out to be violent with a long criminal record and harm the children and/or the parent.
I could be offended that anybody ever thought it was essential to check if I had convictions or other risk factors in my history for working with vulnerable adults and children, just like the only type of HEs here could be offended. But nobody's got a problem with my being checked (including me) - and as abuse is more likely to be perpetrated by somebody in a child's home than it is in a formal setting, it makes absolute sense that all adults should be regularly checked when they have taken a legal step that automatically removes a layer of sight where safeguarding is concerned.
I could also be offended that my bag gets checked when I go into a venue - but I'm not because there is no way of knowing without checking if I'm carrying a weapon or other means of harming people. I know I'm not a murderous terrorist or somebody who thinks a knife is the way to deal with anybody who annoys me - but the guy on the door doesn't know that, does he? I'm also happy that the other people in the queue have their bags checked, too - as I don't want to be on the receiving end of somebody else's aggression if I accidentally knock their arm when they're holding a plastic cup of £5 luke warm Red Stripe. Or to experience an Arena incident.
I'm pretty sure this is a follow up to the huge numbers of children who didn't show up on school registers following lockdowns - there was likely to be a record of a child existing from birth records, child benefit records or suchlike, but no indication of where they are now. State Schools have to report if a child disappears, but if they don't pop up again, they could be out of the country, in private education (although they are generally onboard with the protection as well and also notify the LA of leavers and starters), in unregistered schools, anywhere.
When a child could be anywhere and with anybody, anything could be happening to them - because, well, abusers would say that they were home educators being picked on, wouldn't they?