it's a very naive thing to think that it's just "customers/suppliers" looking at who they're dealing with
not to mention if you're not paying enough for a whole company etc., you need to put your home address there iirc.
Its still no excuse.
Nobody forces anybody to start a business.
If somebody chooses to start a business then they should do grown-up things like having insurance and complying with the law – which includes publishing their business's contact details.
The legal and good manners reasons for publishing a business's contact details far out-weigh any negative ones.
I am sure I am not the only person on this planet who associates alarm bells with small/medium businesses that try to hide their contact details on their website. As a customer it rings alarm bells that they are going to be a pain the neck to deal with if something goes wrong – if a business is trying to bypass such fundamental requirements, then it makes you think about how they feel about e.g. consumer rights law in relation to handling returns.
Yet my info is exposed by business registration and I get junk mail left and right.
do you think everything on the web is just e-commerce?
and if there are no customers who buy products why should there be an impressum?