Please read what I wrote more carefully. It's considered a roast defect by coffee roasting professionals. That doesn't necessarily mean you have to hate it. If for some reason you like 'woodsy' or 'grassy' coffee, more power to you.
My point is that taste is not that subjective, but taste preference may be subjective. If you're a coffee roasting professional, you would attempt to get rid of such flavors since you're not getting the most out of the coffee.
I’m sure I’ve experienced “roast defects” at some point. However, I’ve tried a lot of light roasts — some of which I’ve liked quite a lot — and surely not all of them were afflicted with such defects. What I’m describing as a general character of light roasts (more present flavor components compared to dark roasts since they are less burned away), which I’m characterizing as “green” or “woodsy”, probably isn’t what you mean. You’re fixating on the vocabulary rather than what is being conveyed.
For what it’s worth, I worked as a barista for a spell a long time ago and blind testing is a hobby of mine; I’ve done lots of dueling press pots experimenting with different varieties and brewing techniques. I also have a hobby of trying out new eateries and cafes. I’m a hobbyist, who loves coffee — but this love has been nurtured mostly outside of professional circles.
> You’re fixating on the vocabulary rather than what is being conveyed.
You're conveying meaning with your vocabulary even if you don't mean to. If you don't have the proper words to describe it, that's fine. Like I said, some people even enjoy particular defects in coffee. For instance, growing defects known as 'quakers' have a particular peanuty taste. It's considered undesirable, but some people might like that.
As to your general idea of conveying that light roasts all taste a certain way, I don't think I can agree to that notion. There's such a wide variety of flavors you can cultivate depending on the origin, roasting style, and processing method that you can't really make that generalization.
One thing I will say: many coffees that are advertised as 'light roast', especially in the non-specialty markets, tend to have one or more of the following problems: 1) underroasted (which leads to grassy/green flavors), 2) not actually roasted to 'light' (maybe more medium), 3) poor temperature control, as a result of trying to roast light (leading to 'baked' flavoring), 4) poor coffee selection for a lighter roast, leading to much more green/grassy flavoring as a result.
My point is that taste is not that subjective, but taste preference may be subjective. If you're a coffee roasting professional, you would attempt to get rid of such flavors since you're not getting the most out of the coffee.