I have in this thread and the other discussing it. Several times. Unless you want to go through each seed oil individually, this video going through the evidence sums it up pretty well. He's without a doubt one of the best and most unbiased ones on youtube, which is rare.
If you'd rather go through it here, we can but it's more time consuming. Lastly, I'm not the one making the actual claim though, which is that they are 'killing us', but I'll go through the evidence anyway.
As far as high fructose corn syrup goes, hopefully these two meta-analysis and a narrative review trial comparing the effect on metabolism and bodyfat to fructose, sucrose and glucose will suffice:
Effect of fructose instead of glucose or sucrose on cardiometabolic markers: a systematic review and meta-analysis of isoenergetic intervention trials
Isoenergetic substitution of fructose or HFCS for glucose or sucrose has no significant effect on most of the cardiometabolic markers investigated; however, some results were affected by residual between-study heterogeneity and studies with high or unclear risk of bias.
PROSPERO registration number CRD42016042930.
pubmed.ncbi.nlm.nih.gov
The effect of high-fructose corn syrup vs. sucrose on anthropometric and metabolic parameters: A systematic review and meta-analysis
In conclusion, analysis of data from the literature suggests that HFCS consumption was associated with a higher level of CRP compared to sucrose, whilst no significant changes between the two sweeteners were evident in other anthropometric and metabolic parameters.
High-fructose corn syrup (HFCS) has been speculated to have stronger negative metabolic effects than sucrose. However, given the current equivocality in the field, the aim of the present study was to determine the impact of HFCS use compared to sucrose on anthropometric and metabolic parameters...
pubmed.ncbi.nlm.nih.gov
Sucrose, High-Fructose Corn Syrup, and Fructose, Their Metabolism and Potential Health Effects: What Do We Really Know?
At present, we believe that the following conclusions are warranted. First, there is no unique relationship between HFCS and obesity. Second, there is broad scientific consensus that there are no significant metabolic or endocrine response differences or differences in health-related effects between HFCS and sucrose...
That is not what is happening though. Caring about what is true and what is not true matters. You can't solve a problem if you don't understand it. I don't have any ties to any of this, I want to be healthy and understand what the health data says.