I feel like we need to keep things in perspective. As @rayray points out the vast majority of people crush insects when they see them. The only exception is if they fall into the “pretty insect” category like butterflies. If you disagree with this, I think your living in a bit of a bubble or in a place where pest control has been so successful that there aren’t enough insects left around for people to worry about. When insects are found in the home, the typical mentality is, “time to call the exterminator”. While we can talk about and even disagree about what we would want in a perfect world, we most certainly do not live in that world and never will. Taking specimens even just to promote the appreciation of these creatures is a win in my book for the insects. Collecting rare species can be restricted, but that’s not what we’re talking about here. If we are talking about stable populations and limited sampling (which is generally the case), I see no reason why a person can’t go out and collect and even enjoy collecting.
I also have to ask, would you feel the same way if someone pinned a cockroach from an infestation you had in your house? How is a cockroach any less important than a butterfly?
Perhaps it’s not exactly the same, but for me, I enjoy pressing (and yes killing) plants (even rare plants) because I love them. This may seem strange, but it’s all about the perspective. Collecting allows me to better understand the plants so that I can better explain to people what makes them special. Being able to better explain leads to a better ability to teach. A better ability to teach imparts a better appreciation in others. A better appreciation in others leads to greater thought given to them by the general public. I’m not going to apologize for enjoying this process when it is part of the necessary work to help people understand. Also, I wouldn’t want to bar a novice from the opportunity to have the same experience and teach his or her friends about these creatures. As I said, perhaps you don’t feel the same for plants, but is an insect really more important than the plant that sustains it?
Perhaps I’m of a different mentality because I grew up in the country where death was a common part of life (and there were plenty of times where it was more merciful to put an animal out of its misery than just to leave it suffering), but I really don’t get why so many people are upset with the idea of killing insects.