Factory workers can keep their distance from each other. How are football players meant to do that? Even in training they will get in each others faces when doing defending drills for corners, free kicks. They are breathing at a faster and heavier rate so their breath will travel further and they'll put out more particles into the air. If one player gets infected it could very well spread through not just his team but an opposition team they play. I can see the season starting again but I can also see it grinding to a halt again when players start catching it. They have careers to think about, why put themselves and their futures at risk if they develop lung damage or any of the other damage this can cause.
I've covered most of this in the post above. Whether factory workers (or office workers or wherever else) can keep their distance is up for debate and even more questions remain regarding whether they will - we all know of examples where workers aren't following social distancing now. I accept that there will be far more contact in football and the risks of infections spreading is greater though. The difference is football is far more likely to prevent an infected person returning to work than somebody in another industry. As above, the plan is for players to be tested 24 hours before training/playing and isolating before being cleared to return. So far this process has been working in Germany but we'll know more over the next two weeks.
Players will have their own decisions to make, just like everybody else and nobody should be forced to return if they're not happy to. PL footballers are much more fortunate than most others facing this decision though - most will have the financial security to choose not to return if they feel unsafe, where as most members of the general public won't.