Those don't look like tamper-resistant outlets to me.
New sockets are often just stiff. That's how it is.
Mind you, the "loosy goosey" sockets you are accustomed to, are actually a fire hazard. When contact is poor, a tiny gap will form, and electricity will simply jump across the gap. This action is called "arcing" and makes a LOT of heat and soot, and that tends to make the arcing worse and worse, and it's a death spiral of destruction until you have a fire in the outlet.
So stiff outlets == good. Plug it in totally square (in case it's a tamper-resistant) and push like you mean it. Power plug blades are quite durable. Honestly my biggest problem is breaking off ground pins from having pulled sideways on the cord.