I share the same view as you AnthonyB.
The opposite view is that with more than 200 deaths happening at work each year without fail, isn't this more of an issue than any 'potential' fire catastrophe, or does the 'drip fed' nature of these deaths make it more tolerable?
I think that public opinion is also a driving factor. For example, BLEVE dying in a freak custard explosion at work, because due to the employer not giving him a suitable spreadsheet package he did a hand calc and forgot to carry-the-one, does not affect me or my family. Due to this, I (As Joe Public) would not be interested in the severity of any fine imposed. However, if Morrisons are found to be breaching safety laws meaning that public are put at risk, THAT is of concern to me (As Joe Public) as I take my family in Morrisons, surely we should be entitled to be safe while shopping? We clearly have an actual death vs a potential death, but with H&S laws predominantly protecting employees, and since it is usually employees who get injured/killed, it seems that this is easier for us/them/you/people to stomach.