The ruling starts to undermine the protections that the Equality Act claims to guard. - David Miller

This is straightforward antisemitism. Here is the problem with those who treated any accusation of antisemitism as a witch hunt: they ended up defending people like this, blinding themselves to glaringly obvious red flags.

The concept that an ideology needs protecting is totally ludicrous. What needs protecting are identities, not ideologies ... The same logic could be applied to a white supremacist.

David Miller's description of how the world works is a fantasy of Zionist conspiracy. In form it is similar to more explicitly anti-Jewish antisemitism. And when he talks about Israel's "time-honoured tactic", and in another article about an "age-old Israel lobby tactic" he inadvertently slips into a way of thinking that is much older than antizionism.
David Miller is not articulating a worry that Jews may be over-sensitive about antisemitism or about criticism of Israel. His position is that Jews who allege that there is antisemitism on the left, or on campus, are acting as part of a deliberate and collective conspiracy to lie.