As the nation's federal law enforcement agency, the FBI should have some access to individuals' internet history without the permission of a judge -- that is during an investigation. For example, during a missing person investigation, it would be useful to know what sites the missing person searched as a means to help locate that person. This is a constructive way for using someone's internet search history. When privacy laws are violated, it's time to step back and re-assess the situation. Perhaps consent would be required. Otherwise, there could be a breach of trust between citizens and the government. Where would you draw the line on security and privacy? After the California shootings, the FBI had difficulty accessing the shooter's phone records. There are strict privacy laws in place already. Individuals are protected. Yet, sometimes, you have to make exceptions.
Without question, the FBI should not be allowed to access individuals' internet history without a judge's permission. Like it or not, we are still a nation of laws and internet history is a privacy protection that is constitutionally guaranteed. Want to see my history? Better have probable cause and a warrant to go with it.
I can understand where the FBI might feel they have a good cause to search without a warrant, and honestly, I myself wouldn't be upset a bit if it happened to me. However, there are laws that require a warrant, and the FBI is required to follow these laws. If a person has nothing to hide, they shouldn't be concerned about this, but it could also turn into quite a nuisance.
There is absolutely no way that the FBI should be able to conduct warrantless searches. This is completely against the Constitution and it is a violation of our most fundamental rights. The FBI can't even be bothered to allow the public to look at their records, why should we be subject to them?