I do understand the frustrations, both Messi and Mbappe look very passive out of possession and from a paying fans point of view, workrate is non-negotiable. It’s not exactly uncommon for fans to hurl abuse at their own players. Football fans are fickle, showing a bit passion can easily win them back over.
Also, I said it many times and even though I do rate Mbappe very highly but when he faces pacy wingbacks or fullbacks he’s half the player. Doesn’t have the technical ability in tight spaces nor the work rate or desire to move from the LW position if he’s being shut out.
His nationality is the only thing stopping him from being booed as well, given his ridiculous wages.