That's your problem then. Bioware can't include stupid dialogue just to make every vocal minority happy.
So what? Liara has respect for what Shepard represents (humanity's champion, the only one that can probably stop the Reapers, etc.) but she also has respect for Shepard the person that exists beyond all of that. That isn't creepy either. I think it's clear that Liara's mission in Redemption was her way of showing some final respects towards both the figure that is Shepard and the person that lies underneath. I think what she did was quite honorable, and it's really irritating when people trivialize it by calling her 'obsessed' or 'crazy'.
I consider it very much a case of your mileage may vary since I see it as understandable why some might think it not odd while others would consider it to be quite a bit and more odd.
Personally to me, I feel there is a difference in what and how you keep what you remember someone by. Keeping objects like clothing, photographs, recordings of their voice and such is one thing but I feel it is another to keep the broken torso of the armor in which said someone quite painfully died in and put it in a glass case on display in a living room.
This made worse to me since Liara was a stranger to a Shepard of mine and that Shepard would not have liked to have found that a stranger made a display like this in their living room. I've played Shepards who have been friends with Liara but who were still uncomfortable with this. One was outright angry at her for it because of what it looked like to her with it being in a display case in the living room. She'd have considered it one thing for Liara to keep the armor somewhere private but something else for Liara to keep it on display the way she did.
Basically, It may be that Liara genuinely means it as a way of honoring Shepard and conveying her respects but that does not mean that some player nor their Shepard would be silly to be uncomfortable with her way of doing so. You may consider an option to talk about it with her as stupid but I see dialogue discussing it as being way to deal with some of the unfortunate implications and uncomfortabilities some players and some Shepards may see and feel about it.