You'll encounter the same level of security if you enter the White House Gift Shop - at least I did a couple years ago. Like you experienced, everything must come off and go through x-ray including your belt (even if the belt is ok at airports), empty pockets, etc.

Initially I left my belt on - i figured it was ok at airports, so why not here - at a gift shop. Bad decision. I received a stern warning about my failure to listen to instructions and to remove my belt. What ever happened to, "I'm sorry sir, you forgot your belt", as a way to get the message across? Absolutely no reason to degrade someone about their ability to listen and follow instructions.

It left a bad taste in my mouth and I didn't spend a penny in the shop even though I saw a couple interesting things I may have purchased otherwise.

I have no plans to ever visit the White House Gift Shop again after the hassle I encountered just to enter. What I encountered there was more hassle than most airports.

Last but not least, I took a tour of the White House several years ago. It was an impressive tour and I would love to do it again if given the opportunity. Back then it was just a quick WTMD and x-ray machine for change/pocket items. Based on the hassle of entering the White House Gift Shop, god only knows what the process is to enter the actual White House on a tour (if they're still provided).