Certainly all Muslims (or 'Islamics') should not be blamed for terrorist acts done by Muslims in the name of their religion according to their fundamentalist beliefs. But I do think there are too many repressive Islamic regimes in the world; I do think that there are beliefs, about suitable punishments for various things they don't like such as blasphemy, being gay, being a victim of rape, etc., held by a lot of Muslims that we ought to challenge. So I don't think it's wrong to challenge Islam and Islamism. That is not scapegoating, it's challenging ideologies.
If we were still in a period of Christian crusading and killing of infidels, I'd be saying the same about Christian ideology, or whichever group ideology, or ideology based on any inhumane ideas that was causing problems for others. In the case of the killings at the Boston marathon, at the Paris offices of Charlie Hebdo, of the murder of a British soldier on the street in the UK, of 9/11, and it seems of the recent Orlando shootings, the ideology that drives the killers can be found in the Koran, the 'holy' book of Islam.
I don't see how pretending this isn't so will help change anything. We need to stop saying such attacks have "nothing to do with Islam; that simply isn't true. They may have nothing to do with most people's Islam but they are inspired by writings in the Koran, just as Christian crusaders were inspired by writings in the bible.
The US also needs to seriously address its gun laws. Again, we can't scapegoat gun owners as a group because most of them never commit a crime. But we can say that making it harder for some types of gun to be bought easily might make a difference. There already has been a change in the law about machine guns. Now they need one about assault rifles, at the very least.
I forget how many people have been killed this years by toddlers alone, so it seems a number of Americans are careless with their guns too. That's a separate issue.