Yes, I definitely agree with you, and I think I’ve ranted about it before. Actually, I think his treatment is misogynistic in two respects: his character is treated the way female characters usually are; and the way his death happened – in the first 10 minutes for shock value, with unusual gruesomeness and brutality, and with that fourth-wall-breaking “No resurrections this time” line – shows utter contempt for Loki’s fans, who are understood to be mostly female.
I searched “loki’s death in infinity war” on my blog and came up with this post where I answered a similar question from someone else and also linked to previous rants about it and reblogs of other people’s rants. Here’s another one that I don’t think I linked in that post.
I’m not sure how you feel about Ragnarok, but I’ve also reblogged and/or contributed to a couple of long analyses of how Loki’s discarding in Infinity War was connected to the deflation and ridicule of his character in Ragnarok, which was ultimately a misogynistic fuck-you to his fans: here’s one, here’s another, and here’s a third.