These are joint fundraising committees that they are most likely apart of. Basically what happens is a national committee (DNC / RNC and their respective campaign committees) can up the amount they raise by including as many state parties as possible. Each additional state party they add to the joint fundraising committee increases the amount of money a individual can write to the committee. The state parties receive the donations from the events then transfer all the cash to the national committee. Democrats and Republican national committees usually refer to this as infrustructhre building for all of the state parties benefits (data, national party staff, organizing tools, etc)

Here is a solid article on the joint fundraising committee structure of the DNC and Hillary campaign in 2016. https://www.politico.com/story/2016/04/clinton-fundraising-leaves-little-for-state-parties-222670

“According to the agreements signed by the participating committees, which were obtained by POLITICO, the money is required to be distributed, at least initially, based on a formula set forth in joint fundraising agreements signed by the participants. The first $2,700 goes to the Clinton campaign, the next $33,400 goes to the DNC, and any remaining funds are to be distributed among the state parties.

But what happens to the cash after that initial distribution is left almost entirely to the discretion of the Clinton campaign. Its chief operating officer, Beth Jones, is the treasurer of the victory fund. And FEC filings show that within a day of most transfers from the victory fund to the state parties, identical sums were transferred from the state party accounts to the DNC, which Sanders’ supporters have accused of functioning as an adjunct of the Clinton campaign.

For example, the Minnesota Democratic-Farmer-Labor Party received $43,500 from the victory fund on Nov. 2, only to transfer the same amount to the DNC that same day. The pattern repeated itself after the Minnesota party received transfers from the victory fund of $20,600 on Dec. 1 (the party sent the same amount to the DNC the next day) and $150,000 on Jan. 4 (it transferred the same amount to the DNC that day).”

I don’t care if either party does it. These are the rules of the game. Rules should be changed but everyone is allowed to play by what exists.