Laws about making copies for private use differ from EU country to another. The author is only talking about UK, which has strict laws about copying for private use. For instance, it is illegal to copy CDs [1] or entire books [2] for private use in UK.
In Finland, it is legal to copy CDs (even the ones in public libraries!) [3] and entire books [4] for private use. So, I don't think that 3D printing of furniture is affected in Finland. I can happily continue printing my Ikea chairs.