Its not a loser mentality, its objectivity.
To get to the final of the CL is extremely difficult. Teams who have won the europa league recently include Frankfurt, Sevilla, Villareal, this level of United side. You don't have to be elite to win it, you don't have to be even close. To win the CL you have to be elite, one of the very top teams in Europe. To get there we beat Manchester City, Dortmund and an amazing Ajax side after navigating Inter and Barca in a groups. It was by far a bigger achievement. Teams who win the EL don't even get out of CL groups- regularly.
Not sure in what world recognising that the elite competition is by a huge magnitude much more difficult equates to a loser mentality. I assume Chelsea winning the conference league will be a bigger achievement than us reaching a champions league final too.