M0nica As you have said, there are always two sides to a story but if we accept the ERC viewpoint, it wasn't a great piece of recruiting. In answer to your question about why they appointed him in the first place, this from the EC on 14 May 2019 may help:
'The Commission’s decision followed a competitive selection procedure led by a high-level Search Committee. The Search Committee’s call for applications, launched in July 2018, attracted over 50 high-level applications. Following an evaluation process and interviews with the most promising candidates, the Search Committee presented a shortlist of the three most suitable candidates to Commissioner Moedas. The candidates met with the ERC Scientific Council, who also approved the appointment of Professor Ferrari. Professor Ferrari is appointed by the Commission for a 4-year term of office, renewable once.'