Are you saying that football supporters are hypocrites? Well, I have never ...
To be serious, it's not very surprising that a player who has built up (in Ronaldo's case, tons) of goodwill gets more leeway than some who doesn't perform. This season is a good example - it took a few months before Bruno got serious criticism, because he pretty much carried United the first 1,5 years he was here. This happen in life outside of football also - if someone brings a lot of positive aspects to your life, then it's easier to ignore negative sides. If said person only brings negative aspects to your life bar one positive surprise every other year, then you tend to get annoyed by everything said person does.
As for Lingard, he got a lot of goodwill early on on the back of his FA Cup final goal and that one hotstreak. Add to that him being an academy player, which automatically gives you extra armor against criticism. Then not only did he perform really bad on the pitch, he also started to become a real nuissance of it. Starting with that embarrassing video when our bus was attacked by WH fans. Of course we don't have watertight proof that he has been leaking stuff, but something there has been something iffy with the lack of media attention to his dreadful performances over years. Enhanced by the fact that he got the press to run stories excusing/explaining his dreadful performances with personal issues etc. but now he finally found the real Jesse Lingard again (after two just ok-ish matches in a week) for him to turn utter shit again for the rest of the season.
As for you trying to drag Ronaldo down in your defence of Lingard by pointing to the CL final in Rome - Our team got everything wrong that match and Ronaldo was actually our only threat, albeit just for the first 15 minutes or so when we looked decent.