Partially true, but misleading.

Once 95% is reached , any nodes not upgrading will still be able to use bitcoin on their outdated implementations/wallets , but will no longer validate the new segwit signatures which they already would not create themselves or have paid to them, or pay attention to until confirmed.
So essentially those that choose not to upgrade to segwit, validation will remain the same with old tx's , they just cannot validate segwit tx's which they can accept but won't verify until confirmed.