I don't really see that this is about forcing anyone to choose between one or the other. I see it as every witness who chooses to be a block producer at EOS needing to have the integrity to disclose that they are doing so and letting the community decide if they should remain witness on the Steem blockchain.

For those not in the top 20, there is not really much of an issue. In the top 20, things get a bit different because it takes 17 of the top 20 to approve or reject hardforks. Should a HF come up with what amounts to a conflict of interest between EOS and STEEM the community needs to know if there is a concern about a witness with interests in both blockchains potentially acting more in their self-interest than the blockchain.

Should there be enough with dual interests in the top 20 to influence the HFs and something say got rejected that worked in the favour of EOS... or vice versa.. don't think for a minute it wouldn't create chaos on the respective chain that lost out.

Why wait for the problem to arise. Witnesses wanting to operate on both blockchains should be transparent and let the community make the call.