If you were to canvass the electorate in, say a weeks time, asking them about whether they considered a prospective incoming Labour Government o their Leader was up to the job or a strong leader, then asked them to cite reasons in support of their vote, this incident would not even feature on the radar. Milibands looks might, his perceived nerdiness and nasal voice; His competition with his brother over the leadership position; Union links maybe.
But this will not even be mentioned.
We both agree that a long term, highly public organised movement from the ranks over a period of time would be damaging, no question of that, but this is nothing like that by several orders of magnitude.