Just because 95% of the blocks that the miners produce doesn't mean that non-mining Bitcoin related companies and other Bitcoin users support SegWit (Note: ready to implement != support).
Well no one is forced to implement it; so ready to implement does suggest a small amount of support at least. FWIW, before segwit's activation was set in Bitcoin Core I reached out directly to most of the non-mining Bitcoin related companies that I could fine to specifically prompt for opposition. I received back many positive responses, none opposed, and the only negative comment was from a party that hoped activation would take longer so they would have more time to add support-- it's still possible that they don't support it, apparently not enough to send a respond saying so. After that there was a public discussion on the bitcoin-development list and the only party that argued against it was Tom Zander.
Technically speaking, the threshold is 50.694% (or potentially less depending on luck) for activation as the miners who support SegWit could decide to ignore blocks that lack a signal of support for SegWit.
Yep, only just over half is strictly needed if they're willing to orphan the other almost-half.