"Leicester is a different team to four weeks ago, now they play extremely well," Bilic told reporters on Thursday. "Still I don't understand (Ranieri's sacking) but if we are talking about results, they got what they wanted.
"But it was a bad decision because we are talking about Ranieri... but it's that kind of job. You are the first one to pay the price. Now no one can say it was the wrong decision."
Bilic also praised midfielder Manuel Lanzini, who has scored two goals in his last five appearances, and said the Argentine has stepped up since Dimitri Payet's departure in January.
"He's that kind of a player that wants the ball all of the time and when he's on the ball he's a top player, he's got ideas, he sees the moves before," Bilic said.
"It's not because Payet left. Both of them played amazingly together, but now of course he is the one the players are looking to give the ball, if he is in a good position."
West Ham, who are 11th in the table, will look for their first victory since 2014 against 15th-placed Leicester when the sides meet at the London Stadium.
(Reporting by Aditi Prakash in Bengaluru; Editing by Gareth Jones)
