Lewis Hamilton's former McLaren teammate, Fernando Alonso, has been an open critic of the Honda engine powering McLaren machines since the car giant rejoined Formula One, in 2015. McLaren have been disappointed with the performance and reliability of Honda's engine since day one, with early iterations frequently failing mid-race, and power output being significantly lower than competing Mercedes, Ferrari, and Red Bull engines. Alonso became so frustrated with Honda that he humiliated them at their home race in Japan by comparing their engine to a powerplant from GP2, a Formula One feeder series, which uses weaker engines and less downforce. He did this over team radio, which was broadcast live across the world.
Lewis Hamilton and Fernando Alonso are two drivers you would expect to hold grudges against one another. It could be argued that they denied each other the 2007 World Championship win, as both finished with identical point counts—109—both one point behind Kimi Räikkönen's finishing total of 110. In spite of this, Hamilton has, after watching Alonso's plight from afar, come out in support of his former teammate.
The majority of drivers, commentators, and teams regard the McLaren cars' weakest part, since the Honda partnership began in 2015, to be the engine. The engine development restrictions were scrapped after the end of the 2016 season, which should have allowed Honda to catch up with the competing Renault, Ferrari, and Mercedes engines. Instead, Honda managed to design an even less reliable engine that retains many of the faults possessed by its previous effort.
Alonso, unfortunately, has grown accustomed to driving weak cars far beyond their limit. After the close fight with rookie Hamilton, Alonso moved back to Renault, who were uncompetitive during his stay. He then moved to Ferrari, who failed to produce a car capable of winning the championship during his entire tenure there. Nevertheless, he nearly won the World Championship in 2012, and likely would have if not for an infamous incident involving Romain Grosjean at Spa. A return to McLaren was an exciting prospect for Fernando—doubly so given the historically effective pairing of McLaren and Honda, which has made the recent McHonda partnership all the more disappointing.
It has come to the point where even competitors are putting pressure on Honda, for the sake of closer racing, to make a properly functioning engine. Fernando Alonso, the man to topple the legendary Michael Schumacher at his peak, is stuck in a car that will likely struggle to get out of Q2 for much of the year. Lewis Hamilton can't stand the idea of Fernando having fallen so far. Neither can the rest of the F1 world.