So, this is an interesting article, and I intend to write a fuller reply in a few days when I get the time.
A few quick points (note, I'm not a Plan C member, though I have some time for their ideas, but nothing I say should be taken as representing their opinions):
You say "An article on NovaraMedia by Plan C's Callum Cant frames them as "social strikes" – a “new kind of strike action”... [I]n the case of the Deliveroo and UberEats strikes, it appears one can just slap the label "social strike" on anything that isn't an "official" strike by an established union, involving a ballot mandate, formal notification to the employer, and so on, and say it's not only a “social strike” but a “new kind of strike action”."
The only thing is, is there any sign Callum, or indeed anyone else, actually uses the term social strike to describe the Deliveroo and UberEats strikes? I can't spot it anywhere. If the argument is just that "some of Plan C throw the social strike label around quite enthusiastically, and Callum wrote an excitable article about the UberEats strike, therefore he must think that it's a social strike", that's some pretty sloppy reasoning.
More broadly, on the new/old strike debate, it seems a bit pedantic - if I looked out of my window and saw a wooly mammoth, I might well think something like "blimey, that's new", because it would be entirely unfamiliar to me, even though they existed millions of years ago. Likewise, if some workers carry out a strike in a way that's significantly different to the way that the vast majority of industrial disputes have been conducted during our lifetimes in this country, and someone writes an article pointing out that it's significantly different to the way that the vast majority of industrial disputes have been conducted during our lifetimes in this country, it seems a bit nitpicky to say "your hastily-written buzzfeed listicle which existed mainly to advertise the then-upcoming strike action failed to consider what conditions were like way before any of us were born when it was making the broadly correct point that this strike is significantly different to the way that the vast majority of industrial disputes have been conducted during our lifetimes in this country."
More seriously, your main argument seems to point in some quite minoritarian and substitutionist directions: the working class is folded into the minority of workers who're employed in workplaces with a recognised TUC union. If Al's interview lacks any sense that one can be both a striker engaged in the public sector pay dispute and a Plan C-type engaged in trying to socialise the strike, this piece seems to lack any perspective for what workers in the private sector are supposed to do, other than sit on our hands and wait for the "actually existing labour movement" to rescue us. This is especially perverse given that your piece starts off by talking about the action of the Deliveroo and UberEats couriers, workers who have actually done what you tell us should be impossible by going around, not through, the TUC unions, so that, at least in those workplaces, they are precisely building a new, better, labour movement from scratch.
I could say much more, but I'll stop for now to try and get my thoughts into a slightly clearer order. Also, some recommended reading on the social strike debate:
if you've not seen them already, the AWW's comments on the social strike idea are well worth reading.
And these thoughts from an Australian comrade are also highly recommended (including the discussion in the comments below)
A response from some wobblies
And finally, being a bit cheeky and plugging my own writing on the subject:
I wouldn't start from here
On SATs, strategy and the social strike
More notes on the social strike