you need to work to earn crypto. bounty or airdrop works are "work"
Crowdfunding is an investment. Don't mix apples and oranges.
According to their website, they have had a beta platform since March 2017, I don't think a scam could run for that long without getting a bad name, and I haven't heard any negative feedback about Crowdholding.
Course they will communicate to people on this forum, it is the largest forum for crypto lovers, it's exactly the sort of people they are aiming to get on their platform. If you think that spreading the word about a business on this forum makes it scam, then all ICOs / altcoins are scams as pretty much every ICO has a thread on here.
Way I see it, it's free to sign in so what do you have to lose? If you think you can give good feedback to startups and want to get hold of some crypto this platform is perfect.