Let me play the devil's advocate
It took me three attempts to get to the top of Marcy in the winter. I hiked all three times solo, which can have an effect on how daring you are and how much energy you need to exert. Each trip had its own challenges.
On the first trip, I turned around within a mile of the summit because no one had been up to the top of the mountain in a week, and I was breaking trail, alone and in deep snow, for more than a mile. It was very cold, I was by myself, and my energy level was starting to wane. Frustrated but cautious, I turned around.
The second attempt, a couple of weeks later, ended with me turning around again, this time because it started snowing so hard above Indian Falls that I could barely see five feet in front of me. I trudged along in this heavy snowfall for a while but made the decision to turn back when the volume just didn’t let up. I didn’t want to enter into whiteout conditions above treeline. Doing so would give me pause even in an experienced group because finding your way back down to the marked trail can be difficult and time-consuming. (You can't see, your snowshoe tracks have disappeared, etc.)
I made it on the third try, two weeks later, on a relatively mild day in early March, somewhere around 25 degrees F. This time, it was relatively easy to get to the top. The wind up there, however, was fierce. It knocked me over multiple times, despite my efforts to stay on my feet.
My point is that the conditions on Marcy are quite changeable and hard to predict. The route from the Loj is popular, and you’re likely to see dozens of people, especially on a Saturday or Sunday. The trail might be nicely packed all the way to the top. Then again, it might not be. I agree that in some respects Marcy is easier in the winter than in the summer. But it’s still a remote, potentially dangerous peak, and in shorter days, cold temperatures, and reduced visibility, the stakes go up considerably.