The US has a three part test[1] for what constitutes incitement:

- intent

- imminence

- likelihood

If the UK had speech protections like the US (which I wish they would) then it would fail the imminence and probably the likelihood tests (you rightly note that it is ineffective).

[1] https://uslawexplained.com/incitement

These tweets had 33 views. At least before being made a charge.

I think that puts the likelihood-factor at zero.