Netanyahu has reaffirmed his/Israel's resolve to continue to bomb Hamas in the Gaza Strip despite President Obama's assurance (and one would assume Secretary of State Kerry) to help negotiate things. Obviously the lack of diplomatic success by Obama and his team in Syria and Iraq (as well as the border situation in the United States) probably has left Tel Aviv impressed to say the least.
The real answer as to why Israel has taken matters into their own hands lies not in Washington nor even Tel Aviv but in Cairo. The area known as the Gaza Strip borders Egypt (for about 7 miles) and Israel for around 32 miles. Control of the Gaza Strip was first by Palestine (under Egyptian military authority) in 1948. Israel then captured the Gaza Strip in Six Day War (1967). Pursuant to the Oslo Accords signed in 1993, the Palestinian Authority became the administrative body that governed Palestinian population centers while Israel maintained control of the airspace, territorial waters and border crossings with the exception of the land border with Egypt. In 2005, Israel withdrew from the Gaza Strip under their unilateral disengagement plan. Hamas became de-facto government of the Gaza Strip in 2007.
But for further answers we need to go all the way back to 1979 and the Camp David Accords. Prime Minister Menachem Begin of Israel and President Anwar Sadat of Egypt signed the famous peace agreement (with much assistance from President Jimmy Carter). Just two years later, Sadat would be assassinated allowing Hosni Mubarak to become President of Egypt. Mubarak, like Sadat, kept the peace between Egypt and Israel. Egypt was one of the main players in keeping the Sunnis of the Middle East happy even though the US made no pretenses in favoring Israel over Muslims.
Mubarak, like so many that remain in power for too long, started to use his secret police and torture as a way of keeping in power. Although contrary to the beliefs and values of the United States, Mubarak's expertise in this area would prove beneficial after 9-11. Suspected terrorists caught under rendition would be sent to Egypt to be interrogated (tortured). Mubarak and his cronies didn't perfect their art by watching videos, they of course learned by torturing Egyptians. This lead to Mubarak's ouster as part of the Arab Spring.
While it was easy to see the connection between the Sadat and Anwar regimes to the US, what gets lost in translation is the relationship Morsi (Mubarak's successor) had with the US. Hillary Clinton recognized Morsi's value as a Sunni but could not quite spin his membership in the Muslim Brotherhood as a positive so she kept the relationship from being publicized. As long as Morsi remained in office, the US had a means of keeping the Sunnis from trying to usurp Maliki in Iraq. Once Morsi was replaced with Sisi, the US no longer had any means for communicating with the Sunnis. Hence the ISIL moved into Iraq, Maliki is on the ropes and the US had to turn to their old enemy, Iran. Hence Netanyahu's realization that Obama doesn't have any means of communicating with the Sunnis so his promise to help broker a peace was hollow.
One other thing, none of this should be come as a surprise if you pay attention to the flags. First, here is the flag of Gaza Strip (Palestine);
Next up is Syria;
Next is Iraq;
Notice the similarities, those colors are not by accident. The colors in all of these flags are of the Pan-Arab colors (black, white, green, red), each representing a different Caliphate. The black was the color of the banner of Muhammad; white was used by the Umayyad Caliphate; green was used by the Fatimid Caliphate; and red was the flag held by the Khawarij. These are also the colors of the Arab Revolt of 1916.
Israel has always understood the game and knows they are surrounded. Netanyahu gets the US doesn't have clue and is taking steps to stop Hamas from lobbing missiles. Hamas, which gets its support from Syria, sees the situation in Iraq being an excellent opportunity to split the attention of a weak White House that no longer has a way of reaching the Sunnis (other than through Iran, and who's side do we really think they are on?).