[fen "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"]
They both give Qxf2 as the best move. I used http://analysis.cpuchess.com/ with search time 10 seconds. It's black to move.
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In the given position, Black ultimately has no way to avoid an impending checkmate, hence is lost no matter what. The engines you're consulting are just trying to push that unavoidable mate as far into the future as possible.
1...Qxf2+ does that the best; any other defensive tries lead to a quicker checkmate. For instance:
[Event "?"] [Site "?"] [Date "????.??.??"] [Round "?"] [White "?"] [Black "?"] [Result "*"] [FEN "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"] 1...Qxf2+ ( 1...Rg8 2.Qf6+ Rg7 3.Qxg7# ) ( 1...Qxe5 2.Qxd8# ) 2.Kxf2 Rg8 3.Qf6+ Rg7 4.Qxg7# *
Let me explain what Black can do in this position first, eventually you will understand why Qxf2 isn't the stupidest move which engines are saying.
I want you to see this as a real war and you are the black King here (*not at all being racist! :p )
So anyway, in the battle your opponent's Queen and Bishop's combined force is about to kill you in 2 days, 1st day the Queen invades your g7 kingdom and threatens to kill you on h8 on the 2nd day. As you can not escape your death, you wish to live longer at least! Hence the Engines you possess to help you survive are suggesting the best ways for you to live longer, the engines, as they are robots, they are not sensitive for your feelings of love and lust towards your Black Queen(*again! not being racist or hurting your feelings) and hence says you to send your queen to f2 on the first day so that your opponent's King has to deal with your Queen first before killing you and so you can live longer. I hope you have understood by now, but if not;
In pure chess language:
You are getting mated on g7, you can defend the g7 square by playing 1..Rg8, but 2.Qf6+ will be a forced mate. If 1...Qxe5, then 2.Qxg7 Mate. Hence only 1...Qxf2 will help you prolong the mate by 1 additional move, and that's why computer suggests that as better than anything else.
[FEN "3r3k/1rp2p1p/4b2B/p3P1Q1/3q4/1P1P2P1/P4PBP/1R4K1 b - - 0 28"] 1...Qxf2+ ( 1...Rg8 2.Qf6+ Rg7 3.Qxg7# ) ( 1...Qxe5 2.Qxd8# ) 2.Kxf2 Rg8 3.Qf6+ Rg7 4.Qxg7#
So, sensibly, you can resign in this position if you want to even before Qxf2. But technically, Engines are programmed in such a way that it goes as deep as possible in search of finding the best moves, and here it found Qxf2 that took it the farthest.