Markets work more efficiently if participants are well informed. If the process for selecting a leader of the Parliamentary Party of the Lib Dems was a market, it was inefficient. The decision-maker was the entire membership, relatively few of whom were personally acquainted with the candidates, let alone had worked with them. Election rules restricted the information flow between candidates and members, notably by preventing candidates from getting members' contact details from HQ. In this information deficit a pre-existing high media profile gave a decisive advantage.
From this perspective it is extremely unhelpful and in the long run unwise to reprimand party activists who are in a position to make useful contributions from personal knowledge if they publicly comment on individual parliamentarians' leadership qualities or performance. After all, if military generals were elected by popular vote - not that far fetched an idea, there has been historical precedent - it would hardly be helpful to have a clampdown on informed discussion of whether they were running the war brilliantly, or on the contrary making a complete hash of it.