This is a tremendous pet peeve of mine; people seem to feel entitled to buying advice.
That's one of the reasons for my taking down the list of gear from my profile. I'm always reluctant to dispense advice, especially for stuff that costs a lot of money, and really I dislike telling people how to spend their money in general. When it comes to gear, I think my priorities are kind of an outlier in this hobby anyway. However I try to frame my impressions in such a way as to let people come to their own conclusions, as I like being helpful, but even then it's still something I'm not entirely comfortable with doing.
Some folks want easy answers, flat out requesting I tell them what to buy. Other folks seem to already have exactly what they want in mind and are merely looking for validation. In both these cases, I find they can sometimes get impatient or frustrated when they aren't hearing what they think I should be telling them. Also some people seem to think we live for sitting around giving advice to strangers on the Internet, and they get impatient when their PMs aren't replied to fast enough for their liking.
People need to realize that most impressions from fellow hobbyists are a gift, freely given in the spirit of generosity, and as such they should be respected. I think perhaps there is a growing trend for people to see hobbyist "reviewing" in terms of commodity. Perhaps it stems from a growing number of people entering this hobby trying to give semi-professional reviews? Anyway, the view is that reviews are given as a service in exchange for notoriety in the form of thumbsups, e-props, viewership, subscriptions, etc. In this formulation, people send out PMs not as someone respectfully requesting the advice of someone with more experience, but rather on equal footing, as in "you give me something, I'll give you something" even if it's not explicitly stated.
I've gotten plenty of PMs from well-mannered, nice and friendly individuals however. I am grateful for that.