I know that, however probably 99.99% of those used are the standard stranded conductor ones. Have you ever seen the solid conductor versions available off the shelf in somewhere like Maplin?
Ive never used Maplins, however, the first relevant item upon searching their site yields this in the item description
"Product details
Maplin Cat 5/Cat 5e Shielded Cable RJ45 Connectors 10 Pack
RJ45 crimp-on connectors for use with shielded, stranded twisted pair network cable. A clever design with separate cable guide that allows cores to be aligned in the correct order easily before insertion and crimping. Connections are 50µ" gold plated for reliability. For Cat 6 cabling, use Order Code N19CH (for stranded cables) or N20CH (for solid cables)."
So it would appear that their intended consumer group do, in fact, have a choice.