Not that I think there's a conspiracy, I don't think one has to try very hard to imagine reasons why the powers that be would suppress such discoveries.
Consider for instance how many US citizens are still religious today, and largely govern their lives according to religious beliefs. Consider how the current president has deliberately weakened the separation of church and state by making it legal for churches to be political - pastors of tax-exempt churches can now outright advise congregation on who to vote for.
Discovery of life elsewhere threatens the foundation of a lot of religious dogma.
People always claim this, but I'm not convinced. We've had a million scientific discoveries that for all practical purposes disprove a lot of religious claims. People seem to either just adapt their beliefs, ie. things move from literal to symbolic, or people simply choose not to believe or consider the facts despite clear evidence. I don't think simple facts or evidence will ever seriously threaten religious dogma for at least some portion of the population.
I agree that it will, for some portion, but that portion is ever diminishing.
An irrefutable discovery of complex alien life on another planet would, in my opinion, undoubtedly accelerate that rate of diminishment.
In the mean time, many people use the absence of any such discovery, as proof that earth is inexplicably unique so some magic creator deliberately blessed us to be here on this sacred planet.
Consider for instance how many US citizens are still religious today, and largely govern their lives according to religious beliefs. Consider how the current president has deliberately weakened the separation of church and state by making it legal for churches to be political - pastors of tax-exempt churches can now outright advise congregation on who to vote for.
Discovery of life elsewhere threatens the foundation of a lot of religious dogma.