Yes, the United States should boycott Israel for its civil rights violations. Though Palestiniens have been equally as terrible to Israel, Israel is guilty of many civil rights violations, and as such, the United States should boycott them. At such time as Israel stops these violations, then they could return to good graces.
It does not have a national constitution. A National constitution is a national ethic code the country bases their laws on. Israel lacks one.
What does this country stands for? We can't know, as there is nothing stating the basic morals of this country. As things are now, no law in Israel can be labeled as unconstitutional and revoked, because there is noting providing the basis of what could be considered "constitutional"
It is a tyranny. The country is only providing for its jewish population, leaving all the others to fend for themselves, and even doing things harder for them (will come back to this point later).
Israel wants, Israel do. Until now there are a lot of immoral things going on in that place, including inhuman treatment of people. Their government even refuses to dialogue with Palestine to end the conflict in a peaceful way.
They have, and use, chemical weapons, like white phosphorous (it is illegal internationally)
They have the hasbara, a group dedicated to censor anything putting Israel in a bad light. They work in several languages, and even intervene in the web.
Also, no one in the world gets a massive undeserved reputation. If you hear something all the time, from many different, unrelated sources, it is probably true.
Take all this into account, and think if they deserve a boycott.
Most us and european analysts have shown that boycotts are ineffective and do not result in serious political change. They, in fact, often in trench or exacerbate the problems, as with Russia, china, and less contemporary, inter war germany. The sanctions do place the brunt of the hurt on the citizens, most notably the haredi, and arab israelis, especially bedouins. The boycotts then affect to a lesser degree, the mostly secularization and center left, citizens of the urban areas, like tel aviv. Boycotts essentially strangle the most disadvantaged citizens (a minority in israel) and strengthen the resolve of hardliners by alienating them, rather than allowing dialogues through appropriately mediated diplomacy, this has been effective with countries in the past (who were not led by fundamentalists, unlike palestine, especially Gaza). Most claims of inequality are misjudged due to a lack of legitimate statistics. The proportion of judges in israel that are arab is 9%, compared to 20% of the population being arab, however, there are 180,000 bedouins in the need from whom statistics are not reliably obtained. This would not be the case if bedouins more readily accepted help from the Israeli government to urbanize. Israel has initiatives to increase the proportion of arabs in the government. Israel also gives and organizes the donations of thousands of millions of dollars to Palestine each year, while limiting legitimacy of hamas and the plo, who both steal similarly large amounts of money from the Palestinian people each year.