I'll try to clarify why the scene can still be unnerving (or even more so) for some people even now, but I'll also say: I find it rather unnecessary to incessantly question someone trying to look for some sort of fault rather than just taking them at their word and discuss the feedback. It comes across as not believing them rather than wanting to explore the topic.

So, to explain the dissonance:

Serious content warning for imagery of violence

For the sake of helping it come across I'm going to have to invoke way more exaggerated imagery, just to explain why some could be unnerved. Understand that said imagery and topics are used just to help illustrate the issue, not in relation to the debate. I'm not comparing what Astarion does to a murder or the circumstances the kiss happens in to a murder, I'm trying to explain why the happy faces might be kind of icky for some, so please don't fall into a discussion over this.
Basically, imagine if there was a scene where instead it's Tav getting murdered, even though you asked for something else (similarly to how you're asking for a kiss, not for kneeling or any sort of kinky play). The scene plays as you'd imagine and it's a pretty brutal depiction at that. Except Tav is enthusiastically smiling all along. Uh, is it consensual now? Maybe? The thing is, people will feel that's a disturbing reaction for someone to have to something like that being done to their character if that's not how they envision them, and Tav might even come across as drugged or brainwashed.

Similarly, I'll repeat what I said before in regards to the topic that's popped up again here: Strangers assuming and imposing sexual interests onto you is uncomfortable for reasons that I hope seem obvious, and has been done a few times here and in past threads. Please don't automatically associate people who want the change reverted or made into a milder expression with enjoying non-con or dead dove, unless they've explicitly stated as much.